Multiple felonies would be committed if the pilot bought the gun out of state on behalf of the OP. It would be a straw purchase - period. It does not matter if the final recipient of the gun was legal to purchase/possess that gun or not. So that would be felony number 1 comitted by the pilot.
Felony #2 would be the OP aiding and abetting the pilot making the straw purchase.
Felony #3 would be the OP actually obtaining the gun from an out of source not exempted by 18 USC 922 (b)(3), via using a middle man to obtain that gun.
Felony #4 would be the Pilot aiding and abetting the OP in his obtaining a gun from an out of state source illegally.
I would be willing to bet $100 against a doughnut that the pilot would lose his commercial pilot's license.
Even if he did not lose his license, I would bet that transportation of personal weapons by pilots (other than for official duty), except MAYBE in checked baggage, would be against airline policy and get him fired.
Now that apparently it appears as if Dust wants the pilot to buy him a gun from out of state, that, of course, puts everything in new light. Of course, Dust wasn't going to be right up front at the beginning and say so.