Have any good suggestions?
Don't know what kind of airplane it is and maybe it's not an issue (not an airplane expert) but are you sure that the wireless is not gonna interfere with airplane's systems? Or are you just gonna risk it?
I would think a large part of the driving factor will be data rate and data format.How much data is involved, how fast does it need to be sent,and what form is it in?i.e. are we talking about something simple like low speed serial data or is it a live video feed?For simple low speed data,These guys also have several "duino" wireless boards /modules & sensors:http://www.anarduino.com/And then there always blue-tooth.--- bill
It's hard to beat the unlicensed 315/433MHz modules for cost, the ones with the SAW TX and regenerative RX. They're often ~$2/ea from Asian exporters/eBay. 5 feet is no problem, in fact at that range you could probably push the speed up from the usual 1kbps up closer to 9kbps.