This comes up a lot, and the answer is always the same...

Regionals will be picky about the degree if the market allows it, but market forces should be in your favor for the forseeable future. If you're in a hurry to get hired at a regional it shouldn't be a problem (especially mesa, lakes, etc).

But the odds of getting to a major without the degree are low, and even if you do it will take longer, costing you wages and seniority.

A few not-so-great majors will hire without the degree, and SWA will hire with a 2-year degree but even then you may need to be connected to get on with SWA.

Airlines will hire a college grad over an ATP every time, unless you want to fly the bush in which case the ATP is almost mandatory.