Aircraft bodies form a very good RF shield, so a signal that is already relatively weak like a GPS signal won't work very well... That said, it would be interesting to see if they work any better within the composite body of the 787.

My phone (HTC One) works on planes, but only if I'm next to the window, and even then it can take 10's of minutes to get a fix.

My handheld hiking GPS works slightly better, but still take a while to get a fix.

My old handheld GPS with an external antenna used to work well if I wedged the antenna (on the end of a wire) beneath the window shade, but since 2001 I haven't been game to do that given the drama it could cause...

Maximum speed I've managed to record is 1287 km/hour (confirmed by the IFE display in the plane to within 2 km/hour) which is technically above the speed of sound, although given we had a ~300km/hour tailwind the KIAS would have been much lower.