If you turn on airplane mode and then turn on wifi, how is wifi going to find any connections if it doesn't scan? On both my Note 4 and Note 10.1, if I put them in airplane mode, then turn on wifi, the phone scans for wifi channels as normal. Once it finds a channel and connects, it continues to scan as normal (which of course is irritating!). The wifi radio is a separate entity so while on, it should work the same whether the phone is in airplane mode or not. Of course, maybe other devices don't work like Samsung devices... although, I would think they would if they needed to find wifi channels.