Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
|  | Year Ended December 31, | Year Ended December 31, | Year Ended December 31, | Increase (Decrease) 2018-2017 | Increase (Decrease) 2017-2016 |
| --- | --- | --- | --- | --- | --- |
|  | 2018 | 2017 | 2016 |  |  |
| Revenue passenger miles (millions) (a) | 231,160 | 226,346 | 223,477 | 2.1% | 1.3% |
| Available seat miles (millions) (b) | 282,054 | 276,493 | 273,410 | 2.0% | 1.1% |
| Passenger load factor (percent) (c) | 82.0 | 81.9 | 81.7 | 0.1pts | 0.2pts |
| Yield (cents) (d) | 17.60 | 17.29 | 16.58 | 1.8% | 4.3% |
| Passenger revenue per available seat mile (cents)  (e) | 14.42 | 14.15 | 13.55 | 1.9% | 4.5% |
| Total revenue per available seat mile (cents) (f) | 15.79 | 15.42 | 14.68 | 2.4% | 5.0% |
| Aircraft at end of period | 1,551 | 1,545 | 1,536 | 0.4% | 0.6% |
| Fuel consumption (gallons in millions) | 4,447 | 4,352 | 4,347 | 2.2% | 0.1% |
| Average aircraft fuel price including related taxes (dollars per gallon) | 2.23 | 1.73 | 1.42 | 29.0% | 21.4% |
| Full-time equivalent employees at end of period | 128,900 | 126,600 | 122,300 | 1.8% | 3.5% |
| Operating cost per available seat mile (cents) (g) | 14.85 | 13.88 | 12.83 | 6.9% | 8.2% |
Question:
What was the size of American Airlines fleet in 2017?
Answer:
1,545