A non-aviation degree is better for several reasons...

A aviation degree is based largely on completion of vocational training (flight training) plus some gen-ed requirements. Since an aviation degree is the path of least resistance, the market is flooded with them. Any airline you really want to work for has thousands of applicants for each slot...you want to stand out.

A non-aviation degree means you have more exposure to non-aviation knowledge...ie more well-rounded. Most airline pilots like to talk about anything BUT aviation while on a trip, so you might actually be better off at an interview with some other degree. In many cases the type of degree will not matter however.

If you get a degree in some marketable skill, then you have a fallback position if flying slows down or you have medical issues.