Yeah, but pilots are always officers, which is why you start as an ensign before becoming a lieutenant, however you are still a pilot so you pretty much have no authority in the chain of command.
It's not a matter of lack of authority, as an officer, you're required to act like one, after all.
You'll find pilots in squadrons have plenty of secondary duties (someone's gotta be in charge of loading mission data onto the aircraft, social activity, morale, updating checklists), since they're officers, and are expected to show secondary leadership qualities whilst on duty. And if you're under fire, and you're the officer with a bunch of enlisted blokes guess whose in charge of organizing a defence?
-> Most people think it's a case of "Here are your wings, and here is your commission." In reality, you have to prove you're officer material, and in the RAAF, for instance, your officer qualities are almost more important than your ability to fly, and plenty of good pilots aren't recommended or don't get offers for a pilot slot because they're not team players or good leaders.
I don't think V gave much thought to Ash's rank.
Agreed. Who knows, maybe they chose Lieutenant because they thought the layperson might not know what an 'Ensign' is?