----

**UNITED      STATES**

**SECURITIES      AND EXCHANGE COMMISSION**

**WASHINGTON,      D.C. 20549**

**FORM      10-Q**

| **x**                                                                                                                                                                                                                                                                                                    | **QUARTERLY                REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE                ACT OF                1934**  |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------|
|                                                                                                                                                                                                                                                                                                     |
| For                the quarterly period ended September 30, 2006                                                                                                                                                                                                                                         |
|                                                                                                                                                                                                                                                                                                     |
|                                                                                                                                                                                                                                                                                                     | or                                                                                                                                        |
|                                                                                                                                                                                                                                                                                                     |                                                                                                                                      |
| **o**                                                                                                                                                                                                                                                                                                    | **TRANSITION                REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE                ACT OF                1934** |
|                                                                                                                                                                                                                                                                                                     |                                                                                                                                      |
| For                the transition period                from                                       to |

**KNIGHT      TRANSPORTATION, INC.**

| **Arizona**                                                                                 | **86-0649974**                                                    |
|---------------------------------------------------------------------------------------------|-------------------------------------------------------------------|
| (State                or other jurisdiction ofincorporation                or organization) | (I.R.S.                EmployerIdentification                No.) |

**5601      West Buckeye Road**

**Phoenix,      Arizona**

**85043**

**602-269-2000**

**o**

| Large                accelerated filer x | Accelerated                filer **o** | Non-accelerated                filer **o** |
|------------------------------------------|----------------------------------------|--------------------------------------------|

**o**

----

**KNIGHT      TRANSPORTATION, INC.**

**INDEX**

| **PART                I -****FINANCIAL                INFORMATION** | **Page                Number**                                                                                                                                                                   |
|---------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|                                                                |                                                                                                                                                                                             |
| **Item                1.**                                          | **Financial                Statements**                                                                                                                                                          |   |
|                                                                |                                                                                                                                                                                             |   |
|                                                                | Condensed                Consolidated Balance Sheets as of September 30, 2006 and                December 31, 2005 (Unaudited)                                                                   | 3 |
|                                                                |                                                                                                                                                                                             |   |
|                                                                | Condensed                Consolidated Statements of Income for the three and nine                        months ended September 30, 2006 and 2005 (Unaudited) | 5 |
|                                                                |                                                                                                                                                                                             |   |
|                                                                | Condensed                Consolidated Statements of Cash Flows for the ninemonths                ended September 30, 2006 and 2005 (Unaudited)                                                   | 6 |
|                                                                |                                                                                                                                                                                             |   |
|                                                                | Notes                to Condensed Consolidated Financial Statements (Unaudited)                                                                                                                  | 8 |
|                                                                |                                                                                                                                                                                             |   |
| **Item                2.**                                          | **Management's                Discussion and Analysis of Financial Condition****and                Results of Operation**                                                                        | 14 |
|                                                                |                                                                                                                                                                                             |   |
| **Item                3.**                                          | **Quantitative                and Qualitative Disclosures About Market Risk**                                                                                                                    | 22 |
|                                                                |                                                                                                                                                                                             |   |
| **Item                4.**                                          | **Controls                and Procedures**                                                                                                                                                       | 22 |
|                                                                |                                                                                                                                                                                             |   |
| **Part                II -****OTHER                INFORMATION**    |                                                                                                                                                                                             |
|                                                                |                                                                                                                                                                                             |   |
| **Item                1.**                                          | **Legal                Proceedings**                                                                                                                                                             | 23 |
|                                                                |                                                                                                                                                                                             |   |
| **Item                1A.**                                         | **Risk                Factors**                                                                                                                                                                  | 23 |
|                                                                |                                                                                                                                                                                             |   |
| **Item                2.**                                          | **Unregistered                Sales of Equity Securities and Use of Proceeds**                                                                                                                   | 23 |
|                                                                |                                                                                                                                                                                             |   |
| **Item                3.**                                          | **Defaults                Upon Senior Securities**                                                                                                                                               | 23 |
|                                                                |                                                                                                                                                                                             |   |
| **Item                4.**                                          | **Submission                of Matters to a Vote of Security Holders**                                                                                                                           | 23 |
|                                                                |                                                                                                                                                                                             |   |
| **Item                5.**                                          | **Other                Information**                                                                                                                                                             | 24 |
|                                                                |                                                                                                                                                                                             |   |
| **Item                6.**                                          | **Exhibits**                                                                                                                                                                                     | 24 |
|                                                                |                                                                                                                                                                                             |   |
| **Signatures**                                                      |                                                                                                                                                                                             | 26 |

----

| **PART                I - FINANCIAL INFORMATION**                                                            |
|-------------------------------------------------------------------------------------------------------------------|
| **Item                1.        ****Financial                Statements** |

| **KNIGHT                TRANSPORTATION, INC. AND                SUBSIDIARIES****Condensed                Consolidated Balance Sheets****(unaudited)****As                of September 30, 2006 and December 31, 2005****(In                thousands)** |   |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------|
|                                                                                                                                                                                                                                                    |   |
|                                                                                                                                                                                                                                                    |   | September                30, 2006 |   | December                31, 2005 |   |
|                                                                                                                                                                                                                                                    |   |   |   |   |   |
| **ASSETS**                                                                                                                                                                                                                                              |   |   |   |   |   |
|                                                                                                                                                                                                                                                    |   |   |   |   |   |
| Current                Assets:                                                                                                                                                                                                                          |   |   |   |   |   |
| Cash                and cash equivalents                                                                                                                                                                                                                |   | $ | 10,668 |   | $ | 18,809 |   |
| Short-term                investments                                                                                                                                                                                                                   |   |   | 6,463 |   |   | 2,278 |   |
| Accounts                receivable, net                                                                                                                                                                                                                 |   |   | 84,004 |   |   | 79,848 |   |
| Notes                receivable, net                                                                                                                                                                                                                    |   |   | 270 |   |   | 241 |   |
| Other                current assets                                                                                                                                                                                                                     |   |   | 9,095 |   |   | 3,355 |   |
| Prepaid                expenses                                                                                                                                                                                                                         |   |   | 7,683 |   |   | 7,156 |   |
| Restricted                cash                                                                                                                                                                                                                          |   |   | - |   |   | 211 |   |
| Deferred                tax asset                                                                                                                                                                                                                       |   |   | 8,190 |   |   | 8,533 |   |
|                                                                                                                                                                                                                                                    |   |   |   |   |   |   |   |
| Total                current assets                                                                                                                                                                                                                     |   |   | 126,373 |   |   | 120,431 |   |
|                                                                                                                                                                                                                                                    |   |   |   |   |   |   |   |
| Property                and Equipment:                                                                                                                                                                                                                  |   |   |   |   |   |   |   |
| Land                and improvements                                                                                                                                                                                                                    |   |   | 20,059 |   |   | 18,163 |   |
| Buildings                and improvements                                                                                                                                                                                                               |   |   | 36,163 |   |   | 34,482 |   |
| Furniture                and fixtures                                                                                                                                                                                                                   |   |   | 6,327 |   |   | 7,518 |   |
| Shop                and service equipment                                                                                                                                                                                                               |   |   | 3,655 |   |   | 2,803 |   |
| Revenue                equipment                                                                                                                                                                                                                        |   |   | 481,157 |   |   | 430,048 |   |
| Leasehold                improvements                                                                                                                                                                                                                   |   |   | 440 |   |   | 378 |   |
|                                                                                                                                                                                                                                                    |   |   |   |   |   |   |   |
|                                                                                                                                                                                                                                                    |   |   | 547,801 |   |   | 493,392 |   |
| Less:                Accumulated depreciation and                amortization                                                                                                                                                                           |   |   | (144,304 | ) |   | (141,053 | ) |
|                                                                                                                                                                                                                                                    |   |   |   |   |   |   |   |
| Property                and equipment, net                                                                                                                                                                                                              |   |   | 403,497 |   |   | 352,339 |   |
|                                                                                                                                                                                                                                                    |   |   |   |   |   |   |   |
| Notes                receivable - long-term                                                                                                                                                                                                             |   |   | 407 |   |   | 344 |   |
| Goodwill                                                                                                                                                                                                                                                |   |   | 8,439 |   |   | 8,119 |   |
| Other                assets & restricted cash                                                                                                                                                                                                       |   |   | 5,218 |   |   | 2,594 |   |
|                                                                                                                                                                                                                                                    |   |   |   |   |   |   |   |
|                                                                                                                                                                                                                                                    |   | $ | 543,934 |   | $ | 483,827 |   |

----

Index

| **KNIGHT                TRANSPORTATION, INC. AND SUBSIDIARIES****Condensed                Consolidated Balance Sheets (unaudited) (continued)****As                of September 30, 2006 and December 31, 2005****(In                thousands, except par values)** |   |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------|
|                                                                                                                                                                                                                                                                 |   |   |   |   |   |
|                                                                                                                                                                                                                                                                 |   | September                30, 2006 |   | December                31, 2005 |   |
|                                                                                                                                                                                                                                                                 |   |   |   |   |   |
| **LIABILITIES                AND SHAREHOLDERS' EQUITY**                                                                                                                                                                                                              |   |   |   |   |   |
|                                                                                                                                                                                                                                                                 |   |   |   |   |   |
| Current                Liabilities:                                                                                                                                                                                                                                  |   |   |   |   |   |
| Accounts                payable                                                                                                                                                                                                                                      |   | $ | 12,389 |   | $ | 7,464 |   |
| Accrued                payroll                                                                                                                                                                                                                                       |   |   | 6,524 |   |   | 5,452 |   |
| Accrued                liabilities                                                                                                                                                                                                                                   |   |   | 16,283 |   |   | 13,307 |   |
| Claims                accrual                                                                                                                                                                                                                                        |   |   | 23,214 |   |   | 26,155 |   |
| Other                current liabilities                                                                                                                                                                                                                             |   |   | - |   |   | 211 |   |
| Dividend                payable                                                                                                                                                                                                                                      |   |   | - |   |   | 1,713 |   |
|                                                                                                                                                                                                                                                                 |   |   |   |   |   |   |   |
| Total                current liabilities                                                                                                                                                                                                                             |   |   | 58,410 |   |   | 54,302 |   |
|                                                                                                                                                                                                                                                                 |   |   |   |   |   |   |   |
| Deferred                tax liabilities                                                                                                                                                                                                                              |   |   | 79,155 |   |   | 76,597 |   |
|                                                                                                                                                                                                                                                                 |   |   |   |   |   |   |   |
| Total                liabilities                                                                                                                                                                                                                                     |   |   | 137,565 |   |   | 130,899 |   |
|                                                                                                                                                                                                                                                                 |   |   |   |   |   |   |   |
| Commitments                and Contingencies                                                                                                                                                                                                                         |   |   |   |   |   |   |   |
|                                                                                                                                                                                                                                                                 |   |   |   |   |   |   |   |
| Shareholders'                Equity:                                                                                                                                                                                                                                 |   |   |   |   |   |   |   |
| Preferred                stock, $0.01 par value;50,000                shares authorized;none                issued and outstanding                                                                                                                                   |   |   | - |   |   | - |   |
| Common                stock, $0.01 par value; 100,000 shares authorized;   85,986                and 85,666 shares issued and outstandingat                September 30, 2006 and December 31, 2005, respectively                                     |   |   | 860 |   |   | 857 |   |
| Additional                paid-in capital                                                                                                                                                                                                                            |   |   | 92,936 |   |   | 87,148 |   |
| Retained                earnings                                                                                                                                                                                                                                     |   |   | 312,573 |   |   | 264,923 |   |
|                                                                                                                                                                                                                                                                 |   |   |   |   |   |   |   |
| Total                shareholders' equity                                                                                                                                                                                                                            |   |   | 406,369 |   |   | 352,928 |   |
|                                                                                                                                                                                                                                                                 |   |   |   |   |   |   |   |
|                                                                                                                                                                                                                                                                 |   | $ | 543,934 |   | $ | 483,827 |   |

----

Index

| **KNIGHT                TRANSPORTATION, INC. AND                SUBSIDIARIES****Condensed                Consolidated Statements of Income (unaudited)****(In                thousands, except per share data)** |   |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------|
|                                                                                                                                                                                                             |   |   |   |   |   |
|                                                                                                                                                                                                             |   | Three                Months EndedSeptember                30, |   | Nine                Months EndedSeptember                30, |   |
|                                                                                                                                                                                                             |   | 2006 |   | 2005 |   | 2006 |   | 2005 |   |
| REVENUE:                                                                                                                                                                                                         |   |   |   |   |   |   |   |   |   |
| Revenue,                before fuel surcharge                                                                                                                                                                    |   | $ | 146,555 |   | $ | 127,444 |   | $ | 416,266 |   | $ | 358,241 |   |
| Fuel                surcharge                                                                                                                                                                                    |   |   | 28,117 |   |   | 18,744 |   |   | 73,225 |   |   | 43,996 |   |
| Total                revenue                                                                                                                                                                                     |   |   | 174,672 |   |   | 146,188 |   |   | 489,491 |   |   | 402,237 |   |
| OPERATING                EXPENSES:                                                                                                                                                                               |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Salaries,                wages and benefits                                                                                                                                                                      |   |   | 49,467 |   |   | 41,934 |   |   | 140,530 |   |   | 118,047 |   |
| Fuel                                                                                                                                                                                                             |   |   | 45,528 |   |   | 37,051 |   |   | 124,775 |   |   | 93,084 |   |
| Operations                and maintenance                                                                                                                                                                        |   |   | 9,277 |   |   | 9,067 |   |   | 26,991 |   |   | 24,869 |   |
| Insurance                and claims                                                                                                                                                                              |   |   | 6,929 |   |   | 4,916 |   |   | 18,791 |   |   | 17,221 |   |
| Operating                taxes and licenses                                                                                                                                                                      |   |   | 3,423 |   |   | 3,112 |   |   | 10,015 |   |   | 9,006 |   |
| Communications                                                                                                                                                                                                   |   |   | 1,397 |   |   | 1,009 |   |   | 4,134 |   |   | 2,936 |   |
| Depreciation                and amortization                                                                                                                                                                     |   |   | 15,449 |   |   | 13,328 |   |   | 45,041 |   |   | 38,423 |   |
| Lease                expense - revenue equipment                                                                                                                                                                 |   |   | 106 |   |   | 67 |   |   | 323 |   |   | 67 |   |
| Purchased                transportation                                                                                                                                                                          |   |   | 10,871 |   |   | 8,585 |   |   | 28,609 |   |   | 22,196 |   |
| Miscellaneous                operating expenses                                                                                                                                                                  |   |   | 1,616 |   |   | 2,107 |   |   | 3,646 |   |   | 5,415 |   |
|                                                                                                                                                                                                             |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Total                operating expenses                                                                                                                                                                          |   |   | 144,063 |   |   | 121,176 |   |   | 402,855 |   |   | 331,264 |   |
|                                                                                                                                                                                                             |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Income                from operations                                                                                                                                                                            |   |   | 30,609 |   |   | 25,012 |   |   | 86,636 |   |   | 70,973 |   |
|                                                                                                                                                                                                             |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Interest                and investment income                                                                                                                                                                    |   |   | 301 |   |   | 188 |   |   | 878 |   |   | 442 |   |
| Other                income                                                                                                                                                                                      |   |   | - |   |   | 551 |   |   | - |   |   | 551 |   |
|                                                                                                                                                                                                             |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Income                before income taxes                                                                                                                                                                        |   |   | 30,910 |   |   | 25,751 |   |   | 87,514 |   |   | 71,966 |   |
|                                                                                                                                                                                                             |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Income                taxes                                                                                                                                                                                      |   |   | (12,060 | ) |   | (10,300 | ) |   | (34,710 | ) |   | (28,800 | ) |
|                                                                                                                                                                                                             |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Net                income                                                                                                                                                                                        |   | $ | 18,850 |   | $ | 15,451 |   | $ | 52,804 |   | $ | 43,166 |   |
|                                                                                                                                                                                                             |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Earnings                per common share and common                   share equivalent:                                                                                                                |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Basic                                                                                                                                                                                                            |   | $ | 0.22 |   | $ | 0.18 |   | $ | 0.62 |   | $ | 0.51 |   |
| Diluted                                                                                                                                                                                                          |   | $ | 0.22 |   | $ | 0.18 |   | $ | 0.61 |   | $ | 0.50 |   |
|                                                                                                                                                                                                             |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Weighted                average number of common shares                   and common share equivalents outstanding:                                                                               |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Basic                                                                                                                                                                                                            |   |   | 85,895 |   |   | 85,298 |   |   | 85,823 |   |   | 85,215 |   |
| Diluted                                                                                                                                                                                                          |   |   | 86,922 |   |   | 86,744 |   |   | 87,077 |   |   | 86,715 |   |

----

Index

| **KNIGHT                TRANSPORTATION, INC. AND                SUBSIDIARIES****Condensed                Consolidated Statements of Cash Flows (unaudited)****(In                thousands)** |   |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------|
|                                                                                                                                                                                          |   |   |   |
|                                                                                                                                                                                          |   | Nine                Months EndedSeptember                30, |   |
|                                                                                                                                                                                          |   |   |   |
|                                                                                                                                                                                          |   | 2006 |   | 2005 |   |
| CASH                FLOWS FROM OPERATING ACTIVITIES:                                                                                                                                          |   |   |   |   |   |
|                                                                                                                                                                                          |   |   |   |   |   |
| Net                income                                                                                                                                                                     |   | $ | 52,804 |   | $ | 43,166 |   |
| Adjustments                to reconcile net income to net cash provided by operating                activities:                                                                               |   |   |   |   |   |   |   |
| Depreciation                and amortization                                                                                                                                                  |   |   | 45,041 |   |   | 38,423 |   |
| Gain                on sales of equipment                                                                                                                                                     |   |   | (6,832 | ) |   | (1,783 | ) |
| Gain                on sale of investment                                                                                                                                                     |   |   | - |   |   | (551 | ) |
| Non-cash                compensation expense for issuance of stock to certainmembers                of board of directors                                                                     |   |   | 80 |   |   | 35 |   |
| Provision                for allowance for doubtful accounts                                                                                                                                  |   |   | 293 |   |   | (174 | ) |
| Tax                benefit on stock option exercises                                                                                                                                          |   |   | - |   |   | 1,198 |   |
| Tax                benefits related to stock-based compensation                                                                                                                               |   |   | (1,257 | ) |   | - |   |
| Stock                option expense                                                                                                                                                           |   |   | 2,623 |   |   | - |   |
| Deferred                income taxes                                                                                                                                                          |   |   | 2,901 |   |   | (385 | ) |
| Changes                in assets and liabilities:                                                                                                                                             |   |   |   |   |   |   |   |
| (Increase)                in short-term investments                                                                                                                                           |   |   | (4,185 | ) |   | (18,580 | ) |
| (Increase)                in trade receivables                                                                                                                                                |   |   | (4,448 | ) |   | (10,333 | ) |
| (Increase)                in other current assets                                                                                                                                             |   |   | (307 | ) |   | (806 | ) |
| (Increase)                in prepaid expenses                                                                                                                                                 |   |   | (526 | ) |   | (924 | ) |
| Decrease                in income tax receivable                                                                                                                                              |   |   | - |   |   | 3,216 |   |
| (Increase)                in other assets and restricted assets                                                                                                                               |   |   | (193 | ) |   | (913 | ) |
| (Decrease)                in accounts payable                                                                                                                                                 |   |   | (1,778 | ) |   | (412 | ) |
| Increase                in accrued liabilities, claims accrual and other                                                                                                                      |   |   | 2,151 |   |   | 11,140 |   |
|                                                                                                                                                                                          |   |   |   |   |   |   |   |
| Net                cash provided by operating activities                                                                                                                                      |   |   | 86,367 |   |   | 62,317 |   |
|                                                                                                                                                                                          |   |   |   |   |   |   |   |
| CASH                FLOW FROM INVESTING ACTIVITIES:                                                                                                                                           |   |   |   |   |   |   |   |
|                                                                                                                                                                                          |   |   |   |   |   |   |   |
| Purchase                of property and equipment                                                                                                                                             |   |   | (125,607 | ) |   | (73,665 | ) |
| Proceeds                from sales of equipment                                                                                                                                               |   |   | 37,509 |   |   | 7,617 |   |
| Increase                in notes receivable                                                                                                                                                   |   |   | (93 | ) |   | (253 | ) |
| Acquisition-related                contingent payment                                                                                                                                         |   |   | (320 | ) |   | (3,284 | ) |
| Restricted                cash received                                                                                                                                                       |   |   | - |   |   | (6,805 | ) |
| Proceeds                from sale of investment in Knight Flight Services                                                                                                                     |   |   | - |   |   | 1,388 |   |
| Proceeds                from sale of investment in Concentrek, Inc.                                                                                                                           |   |   | - |   |   | 2,795 |   |
| Increase                in restricted cash                                                                                                                                                    |   |   | (384 | ) |   | - |   |
| Transportation                Resource Partners investment                                                                                                                                    |   |   | (1,836 | ) |   | - |   |
|                                                                                                                                                                                          |   |   |   |   |   |   |   |
| Net                cash used in investing activities                                                                                                                                          |   |   | (90,731 | ) |   | (72,207 | ) |

----

Index

| **KNIGHT                TRANSPORTATION, INC. AND SUBSIDIARIES****Condensed                Consolidated Statements of Cash Flows (unaudited)                (continued)****(In                thousands)** |   |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------|
|                                                                                                                                                                                                      |   | Nine                Months EndedSeptember                30, |   |
|                                                                                                                                                                                                      |   |   |   |
|                                                                                                                                                                                                      |   | 2006 |   | 2005 |   |
|  CASH                FLOW FROM FINANCING ACTIVITIES:                                                                                                                                                 |   |   |   |   |   |
|                                                                                                                                                                                                      |   |   |   |   |   |
| Dividends                paid                                                                                                                                                                             |   |   | (6,866 | ) |   | (2,273 | ) |
| Tax                benefits related to stock-based compensation                                                                                                                                           |   |   | 1,257 |   |   | - |   |
| Payment                of notes payable acquired                                                                                                                                                          |   |   | - |   |   | (6,819 | ) |
| Proceeds                from exercise of stock options                                                                                                                                                    |   |   | 1,832 |   |   | 1,662 |   |
|                                                                                                                                                                                                      |   |   |   |   |   |   |   |
| Net                cash used in financing activities                                                                                                                                                      |   |   | (3,777 | ) |   | (7,430 | ) |
|                                                                                                                                                                                                      |   |   |   |   |   |   |   |
| NET                DECREASE IN CASH AND CASH EQUIVALENTS                                                                                                                                                  |   |   | (8,141 | ) |   | (17,320 | ) |
| CASH                AND CASH EQUIVALENTS, beginning of period                                                                                                                                             |   |   | 18,809 |   |   | 23,155 |   |
|                                                                                                                                                                                                      |   |   |   |   |   |   |   |
| CASH                AND CASH EQUIVALENTS, end of period                                                                                                                                                   |   | $ | 10,668 |   | $ | 5,835 |   |
|                                                                                                                                                                                                      |   |   |   |   |   |   |   |
| SUPPLEMENTAL                DISCLOSURES:                                                                                                                                                                  |   |   |   |   |   |   |   |
|                                                                                                                                                                                                      |   |   |   |   |   |   |   |
| Non-cash                investing and financing transactions:                                                                                                                                             |   |   |   |   |   |   |   |
| Equipment                acquired in accounts payable                                                                                                                                                     |   | $ | 8,604 |   | $ | 4,938 |   |
|                                                                                                                                                                                                      |   |   |   |   |   |   |   |
| Cash                Flow Information:                                                                                                                                                                     |   |   |   |   |   |   |   |
| Income                taxes paid                                                                                                                                                                          |   | $ | 30,371 |   | $ | 21,981 |   |

----

Index

**KNIGHT      TRANSPORTATION, INC. AND      SUBSIDIARIES**

**NOTES      TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (Unaudited)**

**Note      1.**
**Financial      Information**

**Note      2.**
**Stock-Based      Compensation**

----

Index

|                                                                                                                                                                                     |   | Three                Months EndedSeptember                30, 2005 |   | Nine                Months EndedSeptember                30, 2005 |   |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------|--------------------------------------------------------------------|--------|-------------------------------------------------------------------|--------|
|                                                                                                                                                                                     |   |                                                               |   |                                                              |   |
| Net                income, as reported                                                                                                                                                   |   | $                                                                  | 15,451 |                                                              | $      | 43,166 |   |
|                                                                                                                                                                                     |   |                                                               |   |                                                              |   |   |   |
| Deduct                total stock-based compensation expense                   determined under fair-value based method for all                   awards, net of tax |   |                                                               | (533   | )                                                                 |   | (1,600 | ) |
|                                                                                                                                                                                     |   |                                                               |   |                                                              |   |   |   |
| Pro                forma net income                                                                                                                                                      |   | $                                                                  | 14,918 |                                                              | $      | 41,566 |   |
|                                                                                                                                                                                     |   |                                                               |   |                                                              |   |   |   |
| Basic                earnings per share:                                                                                                                                                 |   |                                                               |   |                                                              |   |   |   |
| As                reported                                                                                                                                                               |   | $                                                                  | 0.18   |                                                              | $      | 0.51 |   |
| Pro                forma                                                                                                                                                                 |   | $                                                                  | 0.17   |                                                              | $      | 0.49 |   |
|                                                                                                                                                                                     |   |                                                               |   |                                                              |   |   |   |
| Diluted                earnings per share:                                                                                                                                               |   |                                                               |   |                                                              |   |   |   |
| As                reported                                                                                                                                                               |   | $                                                                  | 0.18   |                                                              | $      | 0.50 |   |
| Pro                forma                                                                                                                                                                 |   | $                                                                  | 0.17   |                                                              | $      | 0.48 |   |

|                                                          | Three                Months EndedSeptember                30, |   | Nine                Months EndedSeptember                30, |
|---------------------------------------------------------------|---------------------------------------------------------------|--------|--------------------------------------------------------------|
|                                                          | 2006                                                          |   | 2005                                                         |   | 2006 |   | 2005 |
| Dividend                yield (1)                             | .45%                                      |   | .30%                                     |   | .43%     |   | .30%     |
| Expected                volatility (2)                        | 33.19%                                    |   | 48.00%                                   |   | 32.38%     |   | 48.00%     |
| Risk-free                interest rate (3)                    | 4.68%                                     |   | 4.00%                                    |   | 5.07%     |   | 4.00%     |
| Expected                terms (4)                             | 7.35                years                 |   | 6.00                years                |   | 8.09                years     |   | 6.19                years     |
| Weighted                average fair value of options granted | $                7.10                     |   | $                7.66                    |   | $                8.63     |   | $                7.44     |

| (1) | The                dividend yield is based on our historical experience and future                expectation of dividend payouts.                                                                                                                                                                                                                                              |
|-----|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| (2) | We                analyzed the volatility of our stock using historical data from January                1,                2003 through the end of the most recent period to estimate the expected                volatility.                                                                                                                                                   |
| (3) | The                risk-free interest rate assumption is based on U.S. Treasury securities                at                a constant maturity with a maturity period that most closely resembles                the                expected term of the stock option award.                                                                                                   |
| (4) | The                expected terms of employee stock options represents the weighted-average                period the stock options are expected to remain outstanding and has                been                determined based on an analysis of historical exercise behavior from                January 1, 2003 through the end of the most recent                period. |

----

Index

|                                     | **Option                Totals**                                                                                                                    |   | **Weighted                Average Exercise****Price                Per Share ($)** |
|------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------|--------|------------------------------------------------------------------------------------|
|                                     |                                                                                                                                                |   |                                                                               |
| Outstanding                12/31/2005    | 4,562,511                                                                                                   |   | 10.68                            |
|                                     |                                                                                                                                                |   |                                                                               |
| Granted                                  | 793,510                                                                                                     |   | 18.67                            |
|                                     |                                                                                                                                                |   |                                                                               |
| Exercised                                | (315,063)                        |   | 5.86                             |
|                                     |                                                                                                                                                |   |                                                                               |
| Forfeited                                | (322,548)                        |   | 9.48                             |
|                                     |                                                                                                                                                |   |                                                                               |
| Outstanding                as of 9/30/06 | 4,718,410                                                                                                   |   | 12.40                            |

|                                              | **Unvested                Option Totals**                                                                     |   | **Weighted                Average Exercise****Price                Per Share ($)** |
|---------------------------------------------------|---------------------------------------------------------------------------------------------------------------|--------|------------------------------------------------------------------------------------|
|                                              |                                                                                                          |   |                                                                               |
| Unvested                Outstanding 6/30/06       | 3,261,301                                                             |   | 13.42                            |
|                                              |                                                                                                          |   |                                                                               |
| Granted                                           | 12,550                                                                |   | 16.23                            |
|                                              |                                                                                                          |   |                                                                               |
| Vested                                            | (342,136)                                              |   | 7.12                             |
|                                              |                                                                                                          |   |                                                                               |
| Forfeited                                         | (133,774)                               |   | 14.68                            |
|                                              |                                                                                                          |   |                                                                               |
| Unvested                Outstanding as of 9/30/06 | 2,797,941                                                             |   | 14.11                            |

----

Index

| **Range                of****Exercise                Prices****($)** |   | **Number****Outstanding** |   | **Weighted                Avg.****Contractual****Years****Remaining** |   | **Weighted                Avg.****Exercise                Price****Per                Share****($)** |   | **Number****Vested                and****Exercisable** |   | **Weighted                Avg.****Exercise                Price****Per                Share for****Vested                and****Exercisable                ($)** |
|----------------------------------------------------------------------|--------|---------------------------|--------|-----------------------------------------------------------------------|--------|------------------------------------------------------------------------------------------------------|--------|--------------------------------------------------------|--------|------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| 0.00                - 10.00                      |   | 1,099,335                 |   | 4.28                                                                  |   | 5.21                                                                   |   | 947,796                            |   | 4.69                                                                                                                     |
| 10.01                - 15.00                     |   | 1,814,919                 |   | 7.56                                                                  |   | 12.10                                                                  |   | 176,722                            |   | 11.80                                                                                                                    |
| 15.01                - 25.00                     |   | 1,804,156                 |   | 9.18                                                                  |   | 17.08                                                                  |   | 795,951                            |   | 15.70                                                                                                                    |
| Overall                Total                     |   | 4,718,410                 |   | 7.42                                                                  |   | 12.40                                                                  |   | 1,920,469                          |   | 9.91                                                                                                                     |

**Note      3.     **
**Earnings      Per Share (in thousands, except per share data)**

|                                                                                                                        |   | Three                Months EndedSeptember                30, |   | Nine                Months EndedSeptember                30, |   |
|-----------------------------------------------------------------------------------------------------------------------------|--------|---------------------------------------------------------------|--------|--------------------------------------------------------------|--------|
|                                                                                                                        |   |                                                          |   |                                                         |   |   |   |   |   |
|                                                                                                                        |   | 2006                                                          |   | 2005                                                         |   | 2006 |   | 2005 |   |
|                                                                                                                        |   |                                                          |   |                                                         |   |   |   |   |   |
| Weighted                average common shares outstanding - basic                                                           |   |                                                          | 85,895 |                                                         |   | 85,298 |   |   | 85,823 |   |   | 85,215 |   |
|                                                                                                                        |   |                                                          |   |                                                         |   |   |   |   |   |   |   |   |   |
| Effect                of stock options                                                                                      |   |                                                          | 1,027  |                                                         |   | 1,446 |   |   | 1,254 |   |   | 1,500 |   |
|                                                                                                                        |   |                                                          |   |                                                         |   |   |   |   |   |   |   |   |   |
| Weighted                average common share and common share                   equivalents outstanding - diluted |   |                                                          | 86,922 |                                                         |   | 86,744 |   |   | 87,077 |   |   | 86,715 |   |
|                                                                                                                        |   |                                                          |   |                                                         |   |   |   |   |   |   |   |   |   |
| Net                income                                                                                                   |   | $                                                             | 18,850 |                                                         | $      | 15,451 |   | $ | 52,804 |   | $ | 43,166 |   |
|                                                                                                                        |   |                                                          |   |                                                         |   |   |   |   |   |   |   |   |   |
| Earnings                per common share and common share                   equivalent                            |   |                                                          |   |                                                         |   |   |   |   |   |   |   |   |   |
| Basic                                                                                                                       |   | $                                                             | 0.22   |                                                         | $      | 0.18 |   | $ | 0.62 |   | $ | 0.51 |   |
| Diluted                                                                                                                     |   | $                                                             | 0.22   |                                                         | $      | 0.18 |   | $ | 0.61 |   | $ | 0.50 |   |
|                                                                                                                        |   |                                                          |   |                                                         |   |   |   |   |   |   |   |   |   |

----

Index

|                                          |   | Three                Months EndedSeptember                30, |    | Nine                Months EndedSeptember                30, |   |
|-----------------------------------------------|--------|---------------------------------------------------------------|---------|--------------------------------------------------------------|--------|
|                                          |   |                                                          |    |                                                         |   |   |   |   |   |
|                                          |   | 2006                                                          |    | 2005                                                         |   | 2006 |   | 2005 |   |
|                                          |   |                                                          |    |                                                         |   |   |   |   |   |
| Number                of anti-dilutive shares |   |                                                          | 847,855 |                                                         |   | 56,100 |   |   | 30,250 |   |   | 50,850 |   |

**Note      4.     **
**Segment      Information**

**Note      5.     **
**New      Accounting Pronouncements**

----

Index

**Note      6.     **
**Commitments      and Contingencies**

**Note      7.     **
**Dividends**

**Note      8.     **
**Other      Assets**

**Note      9.     **
**Assets      Held for Sale**

**Note      10.     **
**Acquisitions**

----

Index

**Item      2.        **
**Management's      Discussion and Analysis of Financial Condition and Results of      Operation**

**Cautionary      Note Regarding Forward-Looking Statements**

*Except      for certain historical information contained herein, this report contains      forward-looking statements that involve risks, assumptions, and uncertainties      which are difficult to predict. All statements, other than statements of      historical fact, are statements that could be deemed forward-looking statements,      including without limitation: any projections of earnings, revenues, or other      financial items; any statement of plans, strategies, and objectives of      management for future operations; any statements concerning proposed new      services or developments; any statements regarding future economic conditions      or      performance; and any statements of belief and any statement of assumptions      underlying any of the foregoing. Words such as "believe," "may," "could,"      "expects," "hopes," "anticipates," and "likely," and variations of these words,      or similar expressions, are intended to identify such forward-looking      statements. Actual events or results could differ materially from those      discussed in forward-looking statements. Factors that could cause or contribute      to such differences include, but are not limited to, those discussed in the      section entitled "*
*Item      1A. Risk Factors*
*,"      set forth below. *

*All      such forward-looking statements speak only as of the date of this Form 10-Q.      You      are cautioned not to place undue reliance on such forward-looking statements.      The Company expressly disclaims any obligation or undertaking to release      publicly any updates or revisions to any forward-looking statements contained      herein to reflect any change in the Company’s expectations with regard thereto      or any change in the events, conditions, or circumstances on which any such      statement is based.*

**Introduction**

***Business      Overview***

***Operating      and Growth Strategy***

----

Index

***Revenue      and Expenses***

***Recent      Results of Operations and Quarter-End Financial      Condition***

| · | Revenue,                before fuel surcharge, increased 15.1%, to $146.6 million from $127.4                million; |
|--------|-----------------------------------------------------------------------------------------------------------------------|
|   |                                                                                                                  |
| · | Net                income increased 22.0%, to $18.9 million from $15.5 million;                and                    |
|   |                                                                                                                  |
| · | Net                income per diluted share increased 22.2%, to $0.22 from $0.18.                                     |

----

Index

**Results      of Operations**

|                                                                                  |   | **(Total                revenue)**Three                MonthsEndedSeptember                30, |                                           | **(Revenue                before fuel surcharge)**Three                MonthsEndedSeptember                30, |   | **(Total                revenue)**Nine                MonthsEndedSeptember                30, |   | **(Revenue                before fuel surcharge)**Nine                MonthsEndedSeptember                30, |                                     |
|---------------------------------------------------------------------------------------|--------|------------------------------------------------------------------------------------------------|------------------------------------------------|----------------------------------------------------------------------------------------------------------------|--------|-----------------------------------------------------------------------------------------------|--------|---------------------------------------------------------------------------------------------------------------|------------------------------------------|
|                                                                                  |   |                                                                                           |                                           |                                                                                                           |   |                                                                                          |   |                                                                                                          |                                     |   |   |   |   |   |   |   |   |
|                                                                                  |   | **2006**                                                                                       |                                           | **2005**                                                                                                       |   | **2006**                                                                                      |   | **2005**                                                                                                      |                                     | **2006** |   | **2005** |   | **2006** |   | **2005** |   |
|                                                                                  |   |                                                                                           |                                           |                                                                                                           |   |                                                                                          |   |                                                                                                          |                                     |   |   |   |   |   |   |   |   |
| Revenue                                                                               |   |                                                                                           | 100.0%                               |                                                                                                           |   | 100.0%                                                                              |   |                                                                                                          | 100.0%                         |   |   | 100.0%                   |   |   | 100.0%                   |   |   | 100.0%                   |   |   | 100.0%                   |   |   | 100.0%                   |   |
|                                                                                  |   |                                                                                           |                                           |                                                                                                           |   |                                                                                          |   |                                                                                                          |                                     |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Operating                expenses:                                                    |   |                                                                                           |                                           |                                                                                                           |   |                                                                                          |   |                                                                                                          |                                     |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Salaries,                wages and benefits                                           |   |                                                                                           | 28.3        |                                                                                                           |   | 28.7                                                            |   |                                                                                                          | 33.8       |   |   | 32.9       |   |   | 28.7       |   |   | 29.3       |   |   | 33.8       |   |   | 33.0       |   |
| Fuel                                                                                  |   |                                                                                           | 26.1        |                                                                                                           |   | 25.3                                                            |   |                                                                                                          | 11.9       |   |   | 14.4       |   |   | 25.5       |   |   | 23.1       |   |   | 12.4       |   |   | 13.7       |   |
| Operations                and maintenance                                             |   |                                                                                           | 5.3         |                                                                                                           |   | 6.2                                                             |   |                                                                                                          | 6.3        |   |   | 7.1       |   |   | 5.5       |   |   | 6.2       |   |   | 6.5       |   |   | 6.9       |   |
| Insurance                and claims                                                   |   |                                                                                           | 4.0         |                                                                                                           |   | 3.4                                                             |   |                                                                                                          | 4.7        |   |   | 3.9       |   |   | 3.8       |   |   | 4.3       |   |   | 4.5       |   |   | 4.8       |   |
| Operating                taxes and licenses                                           |   |                                                                                           | 2.0         |                                                                                                           |   | 2.1                                                             |   |                                                                                                          | 2.3        |   |   | 2.4       |   |   | 2.1       |   |   | 2.2       |   |   | 2.4       |   |   | 2.5       |   |
| Communications                                                                        |   |                                                                                           | 0.8         |                                                                                                           |   | 0.7                                                             |   |                                                                                                          | 1.0        |   |   | 0.8       |   |   | 0.8       |   |   | 0.7       |   |   | 1.0       |   |   | 0.8       |   |
| Depreciation                and                   amortization              |   |                                                                                           | 8.8         |                                                                                                           |   | 9.1                                                             |   |                                                                                                          | 10.5       |   |   | 10.5       |   |   | 9.2       |   |   | 9.6       |   |   | 10.8       |   |   | 10.8       |   |
| Lease                expense - revenue                   equipment          |   |                                                                                           | 0.1         |                                                                                                           |   | 0.0                                                             |   |                                                                                                          | 0.1        |   |   | 0.1       |   |   | 0.1       |   |   | 0.0       |   |   | 0.1       |   |   | 0.0       |   |
| Purchased                transportation                                               |   |                                                                                           | 6.2         |                                                                                                           |   | 5.9                                                             |   |                                                                                                          | 7.4        |   |   | 6.7       |   |   | 5.8       |   |   | 5.6       |   |   | 6.8       |   |   | 6.2       |   |
| Miscellaneous                operating                   expenses           |   |                                                                                           | 0.9         |                                                                                                           |   | 1.5                                                             |   |                                                                                                          | 1.1        |   |   | 1.6       |   |   | 0.8       |   |   | 1.4       |   |   | 0.9       |   |   | 1.5       |   |
| Total                operating expenses                                               |   |                                                                                           | 82.5        |                                                                                                           |   | 82.9                                                            |   |                                                                                                          | 79.1       |   |   | 80.4       |   |   | 82.3       |   |   | 82.4       |   |   | 79.2       |   |   | 80.2       |   |
| Income                from operations                                                 |   |                                                                                           | 17.5        |                                                                                                           |   | 17.1                                                            |   |                                                                                                          | 20.9       |   |   | 19.6       |   |   | 17.7       |   |   | 17.6       |   |   | 20.8       |   |   | 19.8       |   |
| Net                interest, investment, and                   other income |   |                                                                                           | 0.2         |                                                                                                           |   | 0.5                                                             |   |                                                                                                          | 0.2        |   |   | 0.6       |   |   | 0.2       |   |   | 0.3       |   |   | 0.2       |   |   | 0.2       |   |
| Income                before income taxes                                             |   |                                                                                           | 17.7        |                                                                                                           |   | 17.6                                                            |   |                                                                                                          | 21.1       |   |   | 20.2       |   |   | 17.9       |   |   | 17.9       |   |   | 21.0       |   |   | 20.0       |   |
| Income                taxes                                                           |   |                                                                                           | 6.9         |                                                                                                           |   | 7.0                                                             |   |                                                                                                          | 8.2        |   |   | 8.1       |   |   | 7.1       |   |   | 7.2       |   |   | 8.3       |   |   | 8.0       |   |
| Net                income                                                             |   |                                                                                           | 10.8%                           |                                                                                                           |   | 10.6%                                                                               |   |                                                                                                          | 12.9%                          |   |   | 12.1%   |   |   | 10.8%   |   |   | 10.7%   |   |   | 12.7%   |   |   | 12.0%   |   |
|                                                                                  |   |                                                                                           |                                           |                                                                                                           |   |                                                                                          |   |                                                                                                          |                                     |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |

----

Index

**Comparison      of Nine Months and Three Months Ended September 30, 2006 to Nine Months and      Three Months Ended September 30, 2005**

----

Index

----

Index

----

Index

**Liquidity      and Capital Resources**

----

Index

**Off-Balance      Sheet Transactions**

**Critical      Accounting Policies and Estimates**

**Revenue      Recognition.**

**Depreciation.**

**Claims      Accrual**
***.***

----

Index

**Accounting      for Income Taxes.**

**Recent      Accounting Pronouncements.**

**Item      3.        **
**Quantitative      and Qualitative Disclosures About Market Risk**

**Interest      Rate Risk **

**Commodity      Price Risk **

**Item      4.        **
**Controls      and Procedures**

----

Index

**PART      II - OTHER INFORMATION**

**Item      1.       **
**Legal      Proceedings**

**Item      1A.                   **
**Risk      Factors **

**Item      2.       **
**Unregistered      Sales of Equity Securities and **
**Use      **
**of      Proceeds**

**Item      3.       **
**Defaults      Upon Senior Securities**

**Item      4.       **
**Submission      of Matters to a Vote of Security Holders **

----

Index

**Item      5.      **
**Other      Information**

**                                         **

**Item      6.       **
**Exhibits      **

| Exhibit                No. |    | Description                                                                                                                                                                                                                                                      |
|----------------------------|---------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|                       |    |                                                                                                                                                                                                                                                             |
| Exhibit                3   |    | Articles                of Incorporation and Bylaws                                                                                                                                                                                                              |
|                       |    |                                                                                                                                                                                                                                                             |
|                       | (3.1)   | Restated                Articles of Incorporation of the Company. (Incorporated by reference                to                Exhibit 3.1 to the Company's Registration Statement on Form S-1.                No                33-83534.)                       |
|                       |    |                                                                                                                                                                                                                                                             |
|                       | (3.1.1) | First                Amendment to Restated Articles of Incorporation of the Company.                (Incorporated by reference to Exhibit 3.1.1 to the Company's report                on                Form 10-K for the period ended December 31, 2000.) |
|                       |    |                                                                                                                                                                                                                                                             |
|                       | (3.1.2) | Second                Amendment to Restated Articles of Incorporation of the Company.                (Incorporated by reference to Exhibit 3.1.2 to the Company's Registration                Statement on Form S-3 No. 333-72130.)                              |
|                       |    |                                                                                                                                                                                                                                                             |
|                       | (3.1.3) | Third                Amendment to Restated Articles of Incorporation of the Company.                (Incorporated by reference to Exhibit 3.1.3 to the Company's Report                on                Form 10-K for the period ended December 31, 2002.)      |
|                       |    |                                                                                                                                                                                                                                                             |
|                       | (3.2)   | Restated                Bylaws of the Company. (Incorporated by reference to Exhibit 3.2                to the                Company's Registration Statement on Form S-3 No.                333-72130.)                                                        |
|                       |    |                                                                                                                                                                                                                                                             |
|                       | (3.2.1) | First                Amendment to Restated Bylaws of the Company. (Incorporated by reference                to                Exhibit 3.2.1 to the Company's Report on Form 10-K for the period                ended                December 31, 2002.)          |
|                       |    |                                                                                                                                                                                                                                                             |
|                       | (3.2.2) | Second                Amendment to Restated Bylaws of the Company. (Incorporated by reference                to                Exhibit 3.2.1 to the Company's Report on Form 8-K dated March 2,                2005 and                filed on March 4, 2005.)  |
|                       |    |                                                                                                                                                                                                                                                             |
| Exhibit                4   |    | Instruments                defining the rights of security holders, including                indentures                                                                                                                                                          |
|                       |    |                                                                                                                                                                                                                                                             |
|                       | (4.1)   | Articles                4, 10, and 11 of the Restated Articles of Incorporation of the Company.                (Incorporated by reference to Exhibit 3.1 to this Report on Form                10-Q.)                                                            |
|                       |    |                                                                                                                                                                                                                                                             |
|                       | (4.2)   | Sections                2 and 5 of the Restated Bylaws of the Company. (Incorporated by reference                to Exhibit 3.2 to this Report on Form 10-Q.)                                                                                                    |
|                       |    |                                                                                                                                                                                                                                                             |
|                       | (4.3)   | Knight                Transportation, Inc. 2003 Stock Option Plan. (Incorporated by reference                from Exhibit 1 to the Company's Proxy Statement filed April 4, 2003                on                Schedule 14A.)                                 |
|                       |    |                                                                                                                                                                                                                                                             |
|                       | (4.3.1) | First                Amendment to Knight Transportation, Inc. 2003 Stock Option Plan.                (Incorporated by reference to Exhibit 10.10.1 to the Company's Report                of                Form 10-Q for the period ended March 31, 2005.)      |
|                       |    |                                                                                                                                                                                                                                                             |

----

Index

| Exhibit                31 |                            | Section                302 Certifications                                                                                                                                                                                                                                 |
|---------------------------|---------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|                      |                            |                                                                                                                                                                                                                                                                      |
|                      | (31.1)*                         | Certification                pursuant to Item 601(b)(31) of Regulation S-K, as adopted pursuant                to                Section 302 of the Sarbanes-Oxley Act of 2002, by Kevin P. Knight,                the                Company's Chief Executive Officer.  |
|                      |                            |                                                                                                                                                                                                                                                                      |
|                      | (31.2)*                         | Certification                pursuant to Item 601(b)(31) of Regulation S-K, as adopted pursuant                to                Section 302 of the Sarbanes-Oxley Act of 2002, by David A. Jackson,                the                Company's Chief Financial Officer. |
|                      |                            |                                                                                                                                                                                                                                                                      |
| Exhibit                32 |                            | Section                906 Certifications                                                                                                                                                                                                                                 |
|                      |                            |                                                                                                                                                                                                                                                                      |
|                      | (32.1)*                         | Certification                pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section                906 of                the Sarbanes-Oxley Act of 2002, by Kevin P Knight, the Company's                Chief                Executive Officer.              |
|                      |                            |                                                                                                                                                                                                                                                                      |
|                      | (32.2)*                         | Certification                pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section                906 of                the Sarbanes-Oxley Act of 2002, by David A. Jackson, the Company's                Chief                Financial Officer.            |
|                      |                            |
|                      | *Filed                herewith. |

----

Index

**SIGNATURES**

|                                  |   | KNIGHT                TRANSPORTATION, INC.                                                                                                    |
|---------------------------------------|--------|-----------------------------------------------------------------------------------------------------------------------------------------------|
|                                  |   |                                                                                                                                          |
|                                  |   |                                                                                                                                          |
|                                  |   |                                                                                                                                          |
| Date:                November 8, 2006 | By:    | /s/                Kevin P. Knight                                                                                                            |
|                                  |   | Kevin                P. KnightChief                Executive Officer, in his capacity as such and on                behalf of the registrant  |
|                                  |   |                                                                                                                                          |
|                                  |   |                                                                                                                                          |
|                                  |   |                                                                                                                                          |
|                                  |   |                                                                                                                                          |
| Date:                November 8, 2006 | By:    | /s/                David A. Jackson                                                                                                           |
|                                  |   | David                A. JacksonChief                Financial Officer, in his capacity as such and on                behalf of the registrant |