Im dating myself but my mother would have never let me on an airplane as a kid without being in sunday go to meeting clothes. There was much more respect from both ends to the middle in those days.
You're in good company. I remember wearing my Sunday best as a kid when we flew once - and that was for a seat in coach.
Like you mentioned, most families drove for the family vacation. To be able to afford tickets for a family of four was considered a luxury.