Since it was so long ago, it will almost certainly not be an issue as far as getting hired goes.

But I would tell them about it, because they ask "have you ever been arrested or convicted"...they don't ask (or usually care) if it was annulled, sealed, etc).

Also be advised that any airline is required to perform a federal background check on pilot candidates...this involves federal records which include "snapshots" of state and local records. Do you really think that just because your local judge sealed your record that the FBI/CIA will go ahead and delete their copy? Not a chance...so there is still a possibility that your history could be made available to the airline, even though your home-town Burger King would not be able to find it by looking in your local court records.

A large percentage of airline new-hire classes have someone like you who gets removed halfway through training when the background results come in