Not likely to be a problem with American pilots...
since few of them are foreign born or are Moslems. Indeed, a very high percentage of US airline pilots are former military aviators who were vetted with security clearances and firearms training. Once again, the sole reason why many pilots want to be armed is for that final last line of defense inside the cockpit. Right now, all they have is a crash axe. While it was used in one incident of someone breaking into a cockpit, it's hard to use effectively in the narrow confines of the flight deck. Frangilble bullets pretty well eliminate any friendly fire or depressurization concerns.