Yes, AIRFOIL is a Scrabble word!

Letter values in Scrabble US: A 1, I 1, R 1, F 4, O 1, I 1, L 1.

Is it a valid word?

AIRFOIL is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a device that provides reactive force when in motion relative to the surrounding air; can lift or control a plane in flight

Also: control surface.