GPS on an airplane is going to be very marginal at best because the amount of sky you can see from your seat is quite limited and GPS requires something approximating line of sight to 4 satellites or it just thumbs it's nose at you.

In addition to the idea of suction cupping it to the window you also might fare better with an overwing seat--that big sheet of metal out there will bounce the signal to some degree and thus let you see a lot more sky. This degrades the fix but not enough to be meaningful in this situation.

(The GPSes on the airplane itself use an external antenna, they aren't stuck trying to look out through a window.)