<PAGE>
EXHIBIT 10.52


                     AMENDED AND RESTATED SECURITY AGREEMENT


                  This AMENDED AND RESTATED SECURITY AGREEMENT (this
"AGREEMENT"), dated as of January 14, 2005, by and among VisiJet, Inc., a
Delaware corporation ("COMPANY"), each of the parties listed on EXHIBIT A hereto
and their respective endorsees, transferees and assigns (individually, a
"SECURED PARTY", and collectively, the "SECURED PARTIES"), and Renn Capital
Group, Inc., a Texas corporation (the "AGENT"), as agent for the Secured
Parties.

                                   WITNESSETH:

         WHEREAS, pursuant to a Securities Purchase Agreement, dated October 6,
2004, between the Company and certain of the Secured Parties, and a Securities
Purchase Amendment Agreement, dated October 6, 2004, between such parties, the
Company issued to such Secured Parties certain notes and debentures
(collectively, the "PREVIOUS DEBENTURES") which may be converted into shares of
common stock of the Company ("COMMON STOCK") and certain warrants ("PREVIOUS
WARRANTS") to purchase Common Stock; and

         WHEREAS, pursuant to a Securities Purchase Agreement, dated the date
hereof, between the Company and the Secured Parties (the "NEW PURCHASE
AGREEMENT"), the Company has agreed to issue to the Secured Parties certain
debentures (the "DEBENTURES") which may be converted into shares of Common Stock
and certain warrants (the "WARRANTS") to purchase Common Stock; and

         WHEREAS, pursuant to New Purchase Agreement, the Previous Debentures
will be exchanged for Debentures, and the Previous Warrants will be exchanged
for Warrants; and

         WHEREAS, in order to induce certain of the Secured Parties to purchase
the Previous Debentures and the Previous Warrants, the Company agreed to execute
and deliver a Security Agreement, dated as of October 6, 2004 (the "PRIOR
AGREEMENT") for the benefit of such Secured Parties and to grant to them a
security interest in certain property of the Company to secure the prompt
payment, performance and discharge in full of all of Company's obligations under
the Previous Debentures and the Previous Warrants,; and

         WHEREAS, pursuant to Section 15(c) of the Prior Agreement, the
undersigned, constituting all of the parties that executed the Prior Agreement,
desire to amend and restate the Prior Agreement in its entirety as set forth
herein;

         NOW, THEREFORE, in consideration of the agreements herein contained and
for other good and valuable consideration, the receipt and sufficiency of which
is hereby acknowledged, the parties hereto hereby amend and restate the Prior
Agreement to read in its entirety as follows:

         1. CERTAIN DEFINITIONS. As used in this Agreement, the following terms
shall have the meanings set forth in this Section 1. Terms used but not
otherwise defined in this Agreement that are defined in Article 9 of the UCC
(such as "general intangibles" and "proceeds") shall have the respective
meanings given such terms in Article 9 of the UCC.

                  (a) "COLLATERAL" means the collateral in which the Secured
Parties are granted a security interest by this Agreement and which shall
include the following, whether presently owned or existing or hereafter acquired
or coming into existence, and all additions and accessions thereto and all
substitutions and replacements thereof, and all proceeds, products and accounts


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thereof, including, without limitation, all proceeds from the sale or transfer
of the Collateral and of insurance covering the same and of any tort claims in
connection therewith:

                           (i) All goods of the Company, including, without
                  limitations, all machinery, equipment, computers, motor
                  vehicles, trucks, tanks, boats, ships, appliances, furniture,
                  special and general tools, fixtures, test and quality control
                  devices and other equipment of every kind and nature and
                  wherever situated, together with all documents of title and
                  documents representing the same, all additions and accessions
                  thereto, replacements therefor, all parts therefor, and all
                  substitutes for any of the foregoing and all other items used
                  and useful in connection with the Company's businesses and all
                  improvements thereto (collectively, the "EQUIPMENT"); and

                           (ii) All inventory of the Company; and

                           (iii) All of the Company's contract rights and
                  general intangibles, including, without limitation, all
                  partnership interests, stock or other securities, licenses,
                  distribution and other agreements, computer software
                  development rights, leases, franchises, customer lists,
                  quality control procedures, grants and rights, goodwill,
                  trademarks, service marks, trade styles, trade names, patents,
                  patent applications, copyrights, deposit accounts, and income
                  tax refunds (collectively, the "GENERAL INTANGIBLES"); and

                           (iv) All receivables of the Company including all
                  insurance proceeds, and rights to refunds or indemnification
                  whatsoever owing, together with all instruments, all documents
                  of title representing any of the foregoing, all rights in any
                  merchandising, goods, equipment, motor vehicles and trucks
                  which any of the same may represent, and all right, title,
                  security and guaranties with respect to each receivable,
                  including any right of stoppage in transit; and

                           (v) All of the Company's documents, instruments and
                  chattel paper, files, records, books of account, business
                  papers, computer programs and the products and proceeds of all
                  of the foregoing Collateral set forth in clauses (i)-(iv)
                  above.

                  (b) "OBLIGATIONS" means all of the Company's obligations under
this Agreement and the Debentures, in each case, whether now or hereafter
existing, voluntary or involuntary, direct or indirect, absolute or contingent,
liquidated or unliquidated, whether or not jointly owed with others, and whether
or not from time to time decreased or extinguished and later decreased, created
or incurred, and all or any portion of such obligations or liabilities that are
paid, to the extent all or any part of such payment is avoided or recovered
directly or indirectly from the Secured Parties as a preference, fraudulent
transfer or otherwise as such obligations may be amended, supplemented,
converted, extended or modified from time to time.

                  (c) "UCC" means the Uniform Commercial Code, as currently in
effect in the State of Texas.

         2. GRANT OF SECURITY INTEREST. As an inducement for the Secured Parties
to purchase the Debentures and to secure the complete and timely payment,
performance and discharge in full, as the case may be, of all of the
Obligations, the Company hereby, unconditionally and irrevocably, pledges,
grants and hypothecates to the Secured Parties, a continuing security interest
in, a continuing lien upon, an unqualified right to possession and disposition
of and a right of set-off against, in each case to the fullest extent permitted
by law, all of the Company's right, title and interest of whatsoever kind and
nature in and to the Collateral (the "SECURITY Interest").


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         3. REPRESENTATIONS, WARRANTIES, COVENANTS AND AGREEMENTS OF THE
COMPANY. Except as set forth on Schedule A attached hereto, the Company
represents and warrants to, and covenants and agrees with, the Secured Parties
as follows:

                  (a) The Company has the requisite corporate power and
authority to enter into this Agreement and otherwise to carry out its
obligations thereunder. The execution, delivery and performance by the Company
of this Agreement and the filings contemplated therein have been duly authorized
by all necessary action on the part of the Company and no further action is
required by the Company. This Agreement constitutes a legal, valid and binding
obligation of the Company enforceable in accordance with its terms, except as
enforceability may be limited by bankruptcy, insolvency, reorganization,
moratorium or similar laws affecting the enforcement of creditor's rights
generally.

                  (b) The Company represents and warrants that it has no place
of business or offices where its respective books of account and records are
kept (other than temporarily at the offices of its attorneys or accountants) or
places where Collateral is stored or located, except as set forth on SCHEDULE A
attached hereto;

                  (c) The Company is the sole owner of the Collateral (except
for non-exclusive licenses granted by the Company in the ordinary course of
business), free and clear of any liens, security interests, encumbrances, rights
or claims, except as set forth on SCHEDULE B, and is fully authorized to grant
the Security Interest in and to pledge the Collateral. There is not on file in
any governmental or regulatory authority, agency or recording office an
effective financing statement, security agreement, license or transfer or any
notice of any of the foregoing (other than those that have been filed in favor
of the Secured Parties pursuant to this Agreement) covering or affecting any of
the Collateral. So long as this Agreement shall be in effect, the Company shall
not execute and shall not knowingly permit to be on file in any such office or
agency any such financing statement or other document or instrument (except to
the extent filed or recorded in favor of the Secured Parties pursuant to the
terms of this Agreement).

                  (d) No part of the Collateral has been judged invalid or
unenforceable. No written claim has been received that any Collateral or the
Company's use of any Collateral violates the rights of any third party. There
has been no adverse decision to the Company's claim of ownership rights in or
exclusive rights to use the Collateral in any jurisdiction or to the Company's
right to keep and maintain such Collateral in full force and effect, and there
is no proceeding involving said rights pending or, to the best knowledge of the
Company, threatened before any court, judicial body, administrative or
regulatory agency, arbitrator or other governmental authority.

                  (e) The Company shall at all times maintain its books of
account and records relating to the Collateral at its principal place of
business and its Collateral at the locations set forth on SCHEDULE A attached
hereto and may not relocate such books of account and records or tangible
Collateral unless it delivers to the Secured Parties at least thirty (30) days
prior to such relocation (i) written notice of such relocation and the new
location thereof (which must be within the United States) and (ii) evidence that
appropriate financing statements and other necessary documents have been filed
and recorded and other steps have been taken to perfect the Security Interest to
create in favor of the Secured Parties valid, perfected and continuing first
priority liens in the Collateral.

                  (f) This Agreement creates in favor of the Secured Parties a
valid security interest in the Collateral securing the payment and performance
of the Obligations and, upon making the filings described in the immediately
following sentence, a perfected first priority security interest in such
Collateral. Except for the filing of financing statements on Form-1 under the
UCC with the jurisdictions indicated on SCHEDULE B, attached hereto, no
authorization or approval of or filing with or notice to any governmental
authority or regulatory body is required either (i) for the grant by the Company


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<PAGE>

of, or the effectiveness of, the Security Interest granted hereby or for the
execution, delivery and performance of this Agreement by the Company or (ii) for
the perfection of, or exercise by the Secured Parties, or by the Agent on behalf
of the Secured Parties, of their rights and remedies hereunder.

                  (g) On the date of execution of this Agreement, the Company
will deliver to the Agent (on behalf of the Secured Parties) one or more
executed UCC financing statements on Form-1 (or amended UCC financing statements
which shall include the Company's obligations under the Debentures, and shall
include each Secured Party as a "secured party" thereunder) with respect to the
Security Interest for filing with the jurisdictions indicated on SCHEDULE B,
attached hereto and in such other jurisdictions as may be requested by the
Agent. The Company and the Secured Parties agree that as a result of the
exchange of the Previous Debentures for the Debentures, the Previous Debentures
shall not be secured by any security interest on the assets of the Company, and
any previously filed UCC financing statements relating to the Previous
Debentures shall be terminated on the date hereof.

                  (h) The execution, delivery and performance of this Agreement
does not conflict with or cause a breach or default, or an event that with or
without the passage of time or notice, shall constitute a breach or default,
under any agreement to which the Company is a party or by which the Company is
bound. No consent (including, without limitation, from stock holders or
creditors of the Company) is required for the Company to enter into and perform
its obligations hereunder.

                  (i) The Company shall at all times maintain the liens and
Security Interest provided for hereunder as valid and perfected first priority
liens and security interests in the Collateral in favor of the Secured Parties
until this Agreement and the Security Interest hereunder shall terminate
pursuant to Section 11. The Company hereby agrees to defend the same against any
and all persons. The Company shall safeguard and protect all Collateral for the
account of the Secured Parties. At the request of the Secured Parties, the
Company will sign and deliver to the Secured Parties at any time or from time to
time one or more financing statements pursuant to the UCC (or any other
applicable statute) in form reasonably satisfactory to the Secured Parties and
will pay the cost of filing the same in all public offices wherever filing is,
or is deemed by the Secured Parties to be, necessary or desirable to effect the
rights and obligations provided for herein. Without limiting the generality of
the foregoing, the Company shall pay all fees, taxes and other amounts necessary
to maintain the Collateral and the Security Interest hereunder, and the Company
shall obtain and furnish to the Secured Parties from time to time, upon demand,
such releases and/or subordinations of claims and liens which may be required to
maintain the priority of the Security Interest hereunder.

                  (j) The Company will not transfer, pledge, hypothecate,
encumber, license (except for non-exclusive licenses granted by the Company in
the ordinary course of business), sell or otherwise dispose of any of the
Collateral without the prior written consent of the Secured Parties.

                  (k) The Company shall keep and preserve its Equipment,
Inventory and other tangible Collateral in good condition, repair and order and
shall not operate or locate any such Collateral (or cause to be operated or
located) in any area excluded from insurance coverage.

                  (l) The Company shall, within ten (10) days of obtaining
knowledge thereof, advise the Secured Parties promptly, in sufficient detail, of
any substantial change in the Collateral, and of the occurrence of any event
which would have a material adverse effect on the value of the Collateral or on
the Secured Party's security interest therein.

                  (m) The Company shall promptly execute and deliver to the
Secured Parties such further deeds, mortgages, assignments, security agreements,
financing statements or other instruments, documents, certificates and
assurances and take such further action as the Secured Parties may from time to
time request and may in its sole discretion deem necessary to perfect, protect
or enforce its Security Interest.


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<PAGE>

                  (n) The Company shall permit the Secured Parties and its
representatives and agents to inspect the Collateral at any time, and to make
copies of records pertaining to the Collateral as may be requested by the
Secured Parties from time to time.

                  (o) The Company will take all steps reasonably necessary to
diligently pursue and seek to preserve, enforce and collect any rights, claims,
causes of action and accounts receivable in respect of the Collateral.

                  (p) The Company shall promptly notify the Secured Parties in
sufficient detail upon becoming aware of any attachment, garnishment, execution
or other legal process levied against any Collateral and of any other
information received by the Company that may materially affect the value of the
Collateral, the Security Interest or the rights and remedies of the Secured
Parties hereunder.

                  (q) All information heretofore, herein or hereafter supplied
to the Secured Parties by or on behalf of the Company with respect to the
Collateral is accurate and complete in all material respects as of the date
furnished.

                  (r) SCHEDULE A attached hereto contains a list of all of the
subsidiaries of Company.

         4. DEFAULTS. The following events shall be "EVENTS OF DEFAULT":

                  (a) The occurrence of an Event of Default (as defined in the
Debentures) under any of the Debentures;

                  (b) Any representation or warranty of the Company in this
Agreement shall prove to have been incorrect in any material respect when made;

                  (c) The failure by the Company to observe or perform any of
its obligations hereunder for ten (10) days after receipt by the Company of
notice of such failure from the Secured Parties; and

                  (d) Any breach of, or default under, any of the Warrants.

         5. DUTY TO HOLD IN TRUST. Upon the occurrence of any Event of Default
and at any time thereafter, the Company shall, upon receipt by it of any
revenue, income or other sums subject to the Security Interest, whether payable
pursuant to the Debentures or otherwise, or of any check, draft, note, trade
acceptance or other instrument evidencing an obligation to pay any such sum,
hold the same in trust for the Secured Parties and shall forthwith endorse and
transfer any such sums or instruments, or both, to the Secured Parties for
application to the satisfaction of the Obligations.

         6. RIGHTS AND REMEDIES UPON DEFAULT. Each of the Secured Parties hereby
irrevocably appoints Agent to act on its behalf as the Agent hereunder and under
any other document executed in connection herewith, and authorizes the Agent to
take such actions on its behalf and to exercise such powers as are delegated to
the Agent by the terms hereof or thereof, together with such actions and powers
as are reasonably incidental thereto. The provisions of this Paragraph are
solely for the benefit of the Agent and Secured Parties, and the Company shall
not have rights as a third party beneficiary of any of such provisions. The
Agent is authorized to act, in its sole discretion, on behalf of the Secured
Parties as described herein. Upon occurrence of any Event of Default and at any
time thereafter, the Agent (on behalf of the Secured Parties) shall have the


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<PAGE>

right to exercise (on behalf of the Secured Parties) all of the remedies
conferred to the Secured Parties hereunder and under the Debentures, and the
Agent (on behalf of the Secured Parties) shall have all the rights and remedies
of a secured party under the UCC and/or any other applicable law (including the
Uniform Commercial Code of any jurisdiction in which any Collateral is then
located). Without limitation, the Agent (on behalf of the Secured Parties)shall
have the following rights and powers:

                  (a) to take possession of the Collateral and, for that
purpose, enter, with the aid and assistance of any person, any premises where
the Collateral, or any part thereof, is or may be placed and remove the same,
and the Company shall assemble the Collateral and make it available to the Agent
at places which the Agent shall reasonably select, whether at the Company's
premises or elsewhere, and make available to the Agent, without rent, all of the
Company's respective premises and facilities for the purpose of the Secured
Parties taking possession of, removing or putting the Collateral in saleable or
disposable form; and

                  (b) to operate the business of the Company using the
Collateral and shall have the right to assign, sell, lease or otherwise dispose
of and deliver all or any part of the Collateral, at public or private sale or
otherwise, either with or without special conditions or stipulations, for cash
or on credit or for future delivery, in such parcel or parcels and at such time
or times and at such place or places, and upon such terms and conditions as the
Agent may deem commercially reasonable, all without (except as shall be required
by applicable statute and cannot be waived) advertisement or demand upon or
notice to the Company or right of redemption of the Company, which are hereby
expressly waived. Upon each such sale, lease, assignment or other transfer of
Collateral, the Agent may, unless prohibited by applicable law which cannot be
waived, purchase all or any part of the Collateral being sold, free from and
discharged of all trusts, claims, right of redemption and equities of the
Company, which are hereby waived and released.

         Neither Agent nor any of its affiliates or representatives will be
liable for any action taken or omitted to be taken by it or them under this
Agreement in good faith and believed by it or them to be within the discretion
or power conferred upon it or them by this Agreement or be responsible for the
consequences of any error of judgment (except for fraud, gross negligence, or
willful misconduct). Unless indemnified to its satisfaction against loss, cost,
liability, and expense, Agent may not be compelled to do any act under this
Agreement or to take any action toward the execution or enforcement of the
powers created under this Agreement or to prosecute or defend any suit in
respect of this Agreement. If Agent requests instructions from Secured Parties
with respect to any act or action in connection with this Agreement, then Agent
is entitled to refrain (without incurring any liability to anyone by so
refraining) from that act or action unless and until it has received
instructions. In no event, however, may Agent or any of its representatives be
required to take any action that it or they determine could incur for it or them
criminal or onerous civil liability. Without limiting the generality of the
foregoing, no Secured Party has any right of action against Agent as a result of
Agent's acting or refraining from acting under this Agreement in accordance with
instructions of the Secured Parties. EACH SECURED PARTY (IN PROPORTION TO THE
THEN-OUTSTANDING PRINCIPAL AMOUNT OF DEBENTURES) AGREES TO INDEMNIFY AGENT AND
ITS REPRESENTATIVES AND HOLD THEM HARMLESS FROM AND AGAINST ANY AND ALL
LIABILITIES, OBLIGATIONS, LOSSES, DAMAGES, PENALTIES, ACTIONS, JUDGMENTS, SUITS,
COSTS, REASONABLE EXPENSES, AND REASONABLE DISBURSEMENTS OF ANY KIND OR NATURE
WHATSOEVER THAT MAY BE IMPOSED ON, ASSERTED AGAINST, OR INCURRED BY THEM IN ANY
WAY RELATING TO OR ARISING OUT OF THIS AGREEMENT OR ANY ACTION TAKEN OR OMITTED
BY THEM UNDER THIS AGREEMENT. ALTHOUGH AGENT AND ITS REPRESENTATIVES HAVE THE
RIGHT TO BE INDEMNIFIED UNDER THIS AGREEMENT FOR ITS OR THEIR OWN ORDINARY
NEGLIGENCE, AGENT AND ITS REPRESENTATIVES DO NOT HAVE THE RIGHT TO BE
INDEMNIFIED UNDER THIS AGREEMENT FOR ITS OR THEIR OWN FRAUD, GROSS NEGLIGENCE,
OR WILLFUL MISCONDUCT.


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         7. APPLICATIONS OF PROCEEDS. The proceeds of any such sale, lease or
other disposition of the Collateral hereunder shall be applied first, to the
expenses of retaking, holding, storing, processing and preparing for sale,
selling, and the like (including, without limitation, any taxes, fees and other
costs incurred in connection therewith) of the Collateral, to the reasonable
attorneys' fees and expenses incurred by the Secured Parties in enforcing its
rights hereunder and in connection with collecting, storing and disposing of the
Collateral, and then to satisfaction of the Obligations, and to the payment of
any other amounts required by applicable law, after which the Secured Parties
shall pay to the Company any surplus proceeds. If, upon the sale, license or
other disposition of the Collateral, the proceeds thereof are insufficient to
pay all amounts to which the Secured Parties are legally entitled, the Company
will be liable for the deficiency, together with interest thereon, at the rate
of twenty (20%) percent per annum (the "DEFAULT RATE"), and the reasonable fees
of any attorneys employed by the Secured Parties to collect such deficiency, and
all such proceeds shall be allocated among the Secured Parties in proportion to
the amount outstanding under the Debentures. To the extent permitted by
applicable law, the Company waives all claims, damages and demands against the
Secured Parties arising out of the repossession, removal, retention or sale of
the Collateral, unless due to the gross negligence or willful misconduct of the
Secured Parties.

         8. COSTS AND EXPENSES. The Company agrees to pay all out-of-pocket
fees, costs and expenses incurred in connection with any filing required
hereunder, including without limitation, any financing statements, continuation
statements, partial releases and/or termination statements related thereto or
any expenses of any searches reasonably required by the Secured Parties. The
Company shall also pay all other claims and charges which in the reasonable
opinion of the Secured Parties might prejudice, imperil or otherwise affect the
Collateral or the Security Interest therein. The Company will also, upon demand,
pay to the Secured Parties the amount of any and all reasonable expenses,
including the reasonable fees and expenses of its their respective counsel and
of any experts and agents, which the Secured Parties may incur in connection
with (i) the enforcement of this Agreement, (ii) the custody or preservation of,
or the sale of, collection from, or other realization upon, any of the
Collateral, or (iii) the exercise or enforcement of any of the rights of the
Secured Parties under the Debentures. Until so paid, any fees payable hereunder
shall be added to the principal amount of the Debentures, as applicable, and
shall bear interest at the Default Rate.

         9. RESPONSIBILITY FOR COLLATERAL. The Company assumes all liabilities
and responsibility in connection with all Collateral, and the obligations of the
Company hereunder or under the Debentures and the Warrants shall in no way be
affected or diminished by reason of the loss, destruction, damage or theft of
any of the Collateral or its unavailability for any reason.

         10. SECURITY INTEREST ABSOLUTE. All rights of the Secured Parties and
all Obligations of the Company hereunder, shall be absolute and unconditional,
irrespective of: (a) any lack of validity or enforceability of this Agreement,
the Debentures, the Warrants, or any agreement entered into in connection with
the foregoing, or any portion hereof or thereof; (b) any change in the time,
manner or place of payment or performance of, or in any other term of, all or
any of the Obligations, or any other amendment or waiver of or any consent to
any departure from the Debentures, the Warrants, or any other agreement entered
into in connection with the foregoing; (c) any exchange, release or
nonperfection of any of the Collateral, or any release or amendment or waiver of
or consent to departure from any other collateral for, or any guaranty, or any
other security, for all or any of the Obligations; (d) any action by the Secured
Parties to obtain, adjust, settle and cancel in its sole discretion any
insurance claims or matters made or arising in connection with the Collateral;
or (e) any other circumstance which might otherwise constitute any legal or
equitable defense available to the Company, or a discharge of all or any part of


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<PAGE>

the Security Interest granted hereby. Until the Obligations shall have been paid
and performed in full, the rights of the Secured Parties shall continue even if
the Obligations are barred for any reason, including, without limitation, the
running of the statute of limitations or bankruptcy. The Company expressly
waives presentment, protest, notice of protest, demand, notice of nonpayment and
demand for performance. In the event that at any time any transfer of any
Collateral or any payment received by the Secured Parties hereunder shall be
deemed by final order of a court of competent jurisdiction to have been a
voidable preference or fraudulent conveyance under the bankruptcy or insolvency
laws of the United States, or shall be deemed to be otherwise due to any party
other than the Secured Parties, then, in any such event, the Company's
obligations hereunder shall survive cancellation of this Agreement, and shall
not be discharged or satisfied by any prior payment thereof and/or cancellation
of this Agreement, but shall remain a valid and binding obligation enforceable
in accordance with the terms and provisions hereof. The Company waives all right
to require the Secured Parties to proceed against any other person or to apply
any Collateral which the Secured Parties may hold at any time, or to marshal
assets, or to pursue any other remedy. The Company waives any defense arising by
reason of the application of the statute of limitations to any obligation
secured hereby.

         11. TERM OF AGREEMENT. This Agreement and the Security Interest shall
terminate on the date on which all payments under the Debentures have been made
in full and all other Obligations have been paid or discharged. Upon such
termination, the Secured Parties, at the request and at the expense of the
Company, will join in executing any termination statement with respect to any
financing statement executed and filed pursuant to this Agreement.

         12. POWER OF ATTORNEY; FURTHER ASSURANCES.

                  (a) The Company authorizes the Agent, as agent for the Secured
Parties, and does hereby make, constitute and appoint it, and its respective
officers, agents, successors or assigns with full power of substitution, as the
Company's true and lawful attorney-in-fact, with power, in its own name or in
the name of the Company, to, after the occurrence and during the continuance of
an Event of Default, (i) endorse any notes, checks, drafts, money orders, or
other instruments of payment (including payments payable under or in respect of
any policy of insurance) in respect of the Collateral that may come into
possession of the Agent or any Secured Parties; (ii) to sign and endorse any UCC
financing statement or any invoice, freight or express bill, bill of lading,
storage or warehouse receipts, drafts against debtors, assignments,
verifications and notices in connection with accounts, and other documents
relating to the Collateral; (iii) to pay or discharge taxes, liens, security
interests or other encumbrances at any time levied or placed on or threatened
against the Collateral; (iv) to demand, collect, receipt for, compromise, settle
and sue for monies due in respect of the Collateral; and (v) generally, to do,
at the option of the Agent, and at the Company's expense, at any time, or from
time to time, all acts and things which the Agent deems necessary to protect,
preserve and realize upon the Collateral and the Security Interest granted
therein in order to effect the intent of this Agreement, the Debentures, and the
Warrants, all as fully and effectually as the Company might or could do; and the
Company hereby ratifies all that said attorney shall lawfully do or cause to be
done by virtue hereof. This power of attorney is coupled with an interest and
shall be irrevocable for the term of this Agreement and thereafter as long as
any of the Obligations shall be outstanding.

                  (b) On a continuing basis, the Company will make, execute,
acknowledge, deliver, file and record, as the case may be, in the proper filing
and recording places in any jurisdiction, including, without limitation, the
jurisdictions indicated on SCHEDULE B, attached hereto, all such instruments,
and take all such action as may reasonably be deemed necessary or advisable, or
as reasonably requested by the Agent, to perfect the Security Interest granted
hereunder and otherwise to carry out the intent and purposes of this Agreement,
or for assuring and confirming to the Agent the grant or perfection of a
security interest in all the Collateral.


                                       8
<PAGE>

                  (c) The Company hereby irrevocably appoints the Agent as the
Company's attorney-in-fact, with full authority in the place and stead of the
Company and in the name of the Company, from time to time in the Agent's
discretion, to take any action and to execute any instrument which the Agent may
deem necessary or advisable to accomplish the purposes of this Agreement,
including the filing, in its sole discretion, of one or more financing or
continuation statements and amendments thereto, relative to any of the
Collateral without the signature of the Company where permitted by law.

         13. NOTICES. All notices, requests, demands and other communications
hereunder shall be in writing, with copies to all the other parties hereto, and
shall be deemed to have been duly given (i) if delivered by hand, (ii) upon
receipt of proof of sending thereof if sent by facsimile, (iii) upon receipt if
sent by nationally recognized overnight delivery service (receipt requested),
the next business day, or (iv) if mailed by first-class registered or certified
mail, return receipt requested, postage prepaid, four days after posting in the
U.S. mails, in each case if delivered to the following addresses:

         If to the Company:                 VisiJet, Inc.
                                            192 Technology Drive, Suite Q
                                            Irvine, California 92618
                                            Attention: Laurence M. Schreiber
                                            Telephone: (949) 450-1660
                                            Facsimile: (949) 453-9652

         If to the Agent:                   Renn Capital Group, Inc.
                                            8080 North Central Expressway
                                            Suite 210-LP 59
                                            Dallas, TX 75206
                                            Attention:  Robert C. Pearson
                                            Telephone: (214) 891-8294
                                            Facsimile (214) 891-8291

         With copies to:                    Haynes and Boone, LLP
                                            2505 N. Plano Road, Suite 4000
                                            Richardson, Texas  75082
                                            Attention:  David H. Oden
                                            Telephone: (972) 739-6929
                                            Facsimile: (972) 692-9029

         14. OTHER SECURITY. To the extent that the Obligations are now or
hereafter secured by property other than the Collateral or by the guarantee,
endorsement or property of any other person, firm, corporation or other entity,
then the Agent shall have the right, in its sole discretion, to pursue,
relinquish, subordinate, modify or take any other action with respect thereto,
without in any way modifying or affecting any of the Secured Party's rights and
remedies hereunder.

         15. MISCELLANEOUS.

                  (a) No course of dealing between the Company, the Agent and
any Secured Party, nor any failure to exercise, nor any delay in exercising, on
the part of the Agent or any Secured Party, any right, power or privilege
hereunder or under the Debentures shall operate as a waiver thereof; nor shall
any single or partial exercise of any right, power or privilege hereunder or
thereunder preclude any other or further exercise thereof or the exercise of any
other right, power or privilege.


                                       9
<PAGE>

                  (b) All of the rights and remedies of the Secured Parties with
respect to the Collateral, whether established hereby or by the Debentures or by
any other agreements, instruments or documents or by law shall be cumulative and
may be exercised singly or concurrently.

                  (c) This Agreement constitutes the entire agreement of the
parties with respect to the subject matter hereof and is intended to supersede
all prior negotiations, understandings and agreements with respect thereto,
including the Prior Agreement. Any term of this Agreement may be terminated or
amended and the observance of any term of this Agreement may be waived (either
generally or in a particular instance and either retroactively or prospectively)
only with the written consent of the Company and the holders of 75% of the
then-outstanding principal amount of the Debentures. Any termination, amendment
or waiver effected in accordance with this paragraph shall be binding upon each
holder of the Debentures, each future holder of the Debentures, their successors
and assigns, and the Company.

                  (d) In the event that any provision of this Agreement is held
to be invalid, prohibited or unenforceable in any jurisdiction for any reason,
unless such provision is narrowed by judicial construction, this Agreement
shall, as to such jurisdiction, be construed as if such invalid, prohibited or
unenforceable provision had been more narrowly drawn so as not to be invalid,
prohibited or unenforceable. If, notwithstanding the foregoing, any provision of
this Agreement is held to be invalid, prohibited or unenforceable in any
jurisdiction, such provision, as to such jurisdiction, shall be ineffective to
the extent of such invalidity, prohibition or unenforceability without
invalidating the remaining portion of such provision or the other provisions of
this Agreement and without affecting the validity or enforceability of such
provision or the other provisions of this Agreement in any other jurisdiction.

                  (e) No waiver of any breach or default or any right under this
Agreement shall be considered valid unless in writing and signed by the party
giving such waiver, and no such waiver shall be deemed a waiver of any
subsequent breach or default or right, whether of the same or similar nature or
otherwise.

                  (f) This Agreement shall be binding upon and inure to the
benefit of each party hereto and its successors and assigns.

                  (g) Each party shall take such further action and execute and
deliver such further documents as may be necessary or appropriate in order to
carry out the provisions and purposes of this Agreement.

                  (h) This Agreement shall be construed in accordance with the
laws of the State of Texas, except to the extent the validity, perfection or
enforcement of a security interest hereunder in respect of any particular
Collateral which are governed by a jurisdiction other than the State of Texas in
which case such law shall govern. Each of the parties hereto irrevocably submit
to the exclusive jurisdiction of any Texas State or United States Federal court
sitting in Dallas, Texas over any action or proceeding arising out of or
relating to this Agreement, and the parties hereto hereby irrevocably agree that
all claims in respect of such action or proceeding may be heard and determined
in such Texas State or Federal court. The parties hereto agree that a final
judgment in any such action or proceeding shall be conclusive and may be
enforced in other jurisdictions by suit on the judgment or in any other manner
provided by law. The parties hereto further waive any objection to venue in the
State of Texas and any objection to an action or proceeding in the State of
Texas on the basis of forum non conveniens.

                  (i) EACH PARTY HERETO HEREBY AGREES TO WAIVE ITS RESPECTIVE
RIGHTS TO A JURY TRIAL OF ANY CLAIM OR CAUSE OF ACTION BASED UPON OR ARISING OUT
OF THIS AGREEMENT. THE SCOPE OF THIS WAIVER IS INTENDED TO BE ALL ENCOMPASSING
OF ANY DISPUTES THAT MAY BE FILED IN ANY COURT AND THAT RELATE TO THE SUBJECT
MATER OF THIS AGREEMENT, INCLUDING WITHOUT LIMITATION CONTRACT CLAIMS, TORT


                                       10
<PAGE>

CLAIMS, BREACH OF DUTY CLAIMS AND ALL OTHER COMMON LAW AND STATUTORY CLAIMS.
EACH PARTY HERETO ACKNOWLEDGES THAT THIS WAIVER IS A MATERIAL INDUCEMENT FOR
EACH PARTY TO ENTER INTO A BUSINESS RELATIONSHIP, THAT EACH PARTY HAS RELIED ON
THIS WAIVER IN ENTERING INTO THIS AGREEMENT AND THAT EACH PARTY WILL CONTINUE TO
RELY ON THIS WAIVER IN THEIR RELATED FUTURE DEALINGS. EACH PARTY FURTHER
WARRANTS AND REPRESENTS THAT IT HAS REVIEWED THIS WAIVER WITH ITS LEGAL COUNSEL,
AND THAT SUCH PARTY HAS KNOWINGLY AND VOLUNTARILY WAIVES ITS RIGHTS TO A JURY
TRIAL FOLLOWING SUCH CONSULTATION. THIS WAIVER IS IRREVOCABLE, MEANING THAT,
NOTWITHSTANDING ANYTHING HEREIN TO THE CONTRARY, IT MAY NOT BE MODIFIED EITHER
ORALLY OR IN WRITING, AND THIS WAIVER SHALL APPLY TO ANY SUBSEQUENT AMENDMENTS,
RENEWALS AND SUPPLEMENTS OR MODIFICATIONS TO THIS AGREEMENT. IN THE EVENT OF
LITIGATION, THIS AGREEMENT MAY BE FILED AS A WRITTEN CONSENT TO A TRIAL BY THE
COURT.

                  (j) This Agreement may be executed in any number of
counterparts, each of which when so executed shall be deemed to be an original
and, all of which taken together shall constitute one and the same Agreement. In
the event that any signature is delivered by facsimile transmission, such
signature shall create a valid binding obligation of the party executing (or on
whose behalf such signature is executed) the same with the same force and effect
as if such facsimile signature were the original thereof.

                  (k) The Intellectual Property Security Agreement (as defined
in the Prior Agreement) is hereby terminated and shall be of no further force or
effect.



                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]


                                       11
<PAGE>

         IN WITNESS WHEREOF, the parties hereto have caused this Security
Agreement to be duly executed on the day and year first above written.

                                          VISIJET, INC.


                                          By: __________________________________
                                              Name:_____________________________
                                              Title:____________________________



                                          AGENT:

                                          RENN CAPITAL GROUP, INC.


                                          By: __________________________________
                                              Name:_____________________________
                                              Title:____________________________



                                       12
<PAGE>

                                         SECURED PARTY


                                         _______________________________________
                                         [Name of Secured Party]


                                          By: __________________________________
                                          Title:________________________________



           [SIGNATURE PAGE TO AMENDED AND RESTATED SECURITY AGREEMENT]

<PAGE>

                                    EXHIBIT A
                                    ---------


Renaissance Capital Growth & Income Fund III, Inc.
Renaissance US Growth Investment Trust PLC
BFS US Special Opportunities Trust PLC
Roaring Fork Capital SBIC, LP
Republic Aggressive Growth
Little Gem Life Sciences Fund, LLC
Omega Capital
Bushido Capital Master Fund L.P.
Bridges & Pipes LLC
LibertyView Special Opportunities Fund, LP
Little Gem Life Sciences Fund, LLC
Gamma Opportunity Capital Partners, LP
Alpha Capital Aktiengesellschaft
Greenwich Growth Fund Ltd.
Corsair Capital Partners, LP
Corsair Capital Partners Ltd.
Corsair Capital Partners 100 LP

<PAGE>

                                   SCHEDULE A
                                   ----------


Principal Place of Business of the Company:
-------------------------------------------

Visijet, Inc.
192Q Technology Dr.
Irvine Ca. 92618


Locations where collateral is located:
--------------------------------------

Visijet, Inc.
188D Technology Dr.
Irvine, Ca. 92618

Gebauer Medzintechnik GmbH
Monsbachstr 7/1
75242 Neuhausen
Germany


Subsidiaries of the Company
---------------------------

Advanced Refractive Technologies
(Wholly owned inactive Sub)


Exceptions to Representations and Warranties Under Section 3 of the Amended and
-------------------------------------------------------------------------------
Restated Security Agreement
---------------------------


Existing Security Interests:
----------------------------

HIT Credit Union - All assets - See attached executed payoff letter.
Bushido Capital Partners Ltd - All Assets - See attached perfected UCC-1 filing
dated October 7, 2004


Jurisdictions:
--------------

Delaware Corporation
Principal place of business is California
Distribution and Marketing Agreement with Gebauer governed by German Law

<PAGE>

                                   SCHEDULE B
                                   ----------



Existing Security Interests:
----------------------------

HIT Credit Union - All assets - See attached executed payoff letter.
Bushido Capital Partners Ltd - All Assets - See attached perfected UCC-1 filing
dated October 7, 2004


Jurisdictions:
--------------

Delaware Corporation
Principal place of business is California
Distribution and Marketing Agreement with Gebauer governed by German Law