2 adjectives to describe speedster

Now the watchers saw it, slipping through some tenuous higher cloud-banks that had begun to gather, a lean, swift, wasplike speedster: one of the Air Control Board'sthe A.C.B.'smost rapid aerial police planes.

Now the watchers saw it, slipping through some tenuous higher cloud-banks that had begun to gather, a lean, swift, wasplike speedster: one of the Air Control Board'sthe A.C.B.'smost rapid aerial police planes.

2 adjectives to describe  speedster