
Okay. Now we've got an inclined PLANE.
The Big Bang Theory Season 1, Episode 2

...was watching over the PLANE.
The Big Bang Theory Season 8, Episode 23

as the guy in
the PLANE crash
The Big Bang Theory Season 12, Episode 9

Come on,
I spent an entire PLANE ride with you
The Big Bang Theory Season 10, Episode 22

Rent a PLANE, write it in the sky.
The Big Bang Theory Season 9, Episode 12