Tough. That may not be expunged in the federal database, either by design or admin errors.

I'm not entirely certain these days how much access the air carriers have to the data base, but the airport SIDA authorities would. An expungement should not count for SIDA, but they might still see the arrest.

Airlines these days are more limited by state employment laws, but that depends on the state. They are more likely to ask only about arrests, vice convictions, these days.

I will say that most of us who have been around management and hiring can be pretty tolerant of youthful mistakes, say at age 13 or maybe even age 23. The brain is not fully developed until age 25 or so, and judgement is the known weakness (that's why you have to be 25 to rent a car, insurance rules speak cold hard truth). They also say a person's personality and identity is full developed by age 30...

But if I somehow found out an applicant had a theft issue after age 30, that would be a huge red flag, essentially no-go for me without some serious mitigating circumstances (I can't even imagine what that would be). That's for any job, but most especially aviation, where trust and integrity are vital.

So I don't have a real good answer. It would depend on what questions the airlines ask (look up the applications, they are all online), and how much info they can obtain. Keep in mind there are also private databases which may capture court records (which can be searched online) and retain them forever... 1st amendment would probably prevent the government from forcing an expungement of such a private database.

Also, not a good idea to lie to an airline, if you get caught you would be fired, and probably be finished in 121, which is not what you want after spending $100K and a few years to get to 1500 hours.