Number + 架 + Noun
架 (jià) is a measure word used to count machines, aircraft, and large instruments. It is placed between a number and a noun, as in 两架飞机 (two airplanes). It is the standard classifier for planes and similar equipment.
机场停着三架飞机。
Jīchǎng tíng zhe sān jià fēijī.
There are three airplanes parked at the airport.
他们出动了两架直升机去救援。
Tāmen chūdòng le liǎng jià zhíshēngjī qù jiùyuán.
They dispatched two helicopters for the rescue.
博物馆里展出了一架老式战斗机。
Bówùguǎn lǐ zhǎnchū le yí jià lǎoshì zhàndòujī.
An old-fashioned fighter plane is on display in the museum.