Don't even bother taking you GPS along!
Looking at the EMI PED list for my airline, I see "PROHIBITED: ...walkie talkie, satellite receivers, AM/FM radios...". So, I sure don't know about Futura's policy, but would be surprised if they would allow its use.
Another point is that it probably would not work. I tried it once on a ferry flight on a MD-80 and it didn't work from any of the cabin windows. As a matter of fact the only place it worked was by holding the antenna against the rear cockpit windows!
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... cut my wings and I'll die ...