Earbuds win on weight and packability: a case the size of a matchbox, and you can sleep with one ear free. Over-ear headphones win on battery life and comfort for long listening sessions.
For flights under six hours, earbuds with active noise cancelling are usually enough. Beyond that, the clamping force of over-ear headphones starts to matter more than the spec sheet — pick memory-foam pads over hard plastic.
If you carry both, the practical rule is: earbuds for the airport, over-ear for the cruise. Neither needs to be expensive to be good at that job.