I have looked at other threads similar to what I am asking in this but it is hard to get a definitive answer from most. I am currently enrolled in a 4 year university for a BS in political science and I am looking at just making it by with college tuition. I have always have had a passion for aviation and there is no doubt that it is the career for me. I am only going to college with the intent to check the box for "has a college degree" when it comes time for resumes and job applications. The problem I face is going to school for a degree I will never use and frankly do not enjoy learning. The two thoughts I have are one transfer to an aviation college. And two, which is why I am here to see if its even possible...
A lot of people recommend getting a degree outside of aviation to fall back on if something goes wrong with your aviation career, which I would agree with in general. However, I think most people overestimate the "backup" value of a degree, as it will likely be difficult to get a job in the "backup degree" field down the road if the degree is not recent and you have no experience, or at least no recent experience, in that field. You say you do not enjoy learning Political Science, so if you find you are not motivated and your academic performance is suffering as a result, it may be worth switching to an Aviation major if you would be more motivated to complete the degree.
What I am here to really ask is it not only possible but likely to happen for a person without a college degree to get employed and fly for a regional such as Envoy then use their guaranteed interview with American to land a job with a major later on? All without having a college degree.
That would absolutely be possible in theory, but it would not be guaranteed to work out, and it would be imprudent to put all your eggs in one basket like that if you have the opportunity to make yourself eligible for the rest of the majors by getting a degree. As others have pointed out, the flow from Envoy to AA could always be cancelled in the future; in the past Mesaba and Compass had flows to Northwest and Delta respectively that were cancelled. Envoy could also be shut down similar to Comair before you get the chance to flow; actually a few years ago I believe AA threatened to do just this if Envoy's pilot group didn't ratify a concessionary contract. American itself could even go out of business before you get the chance to flow- consider how many historical airlines are no longer existent. At the end of the day there are few truly career-level airlines, so it would be wise to make yourself eligible to be hired at as many of them as possible.
Pretty much all of the legacy airlines require a degree, and it seems that at LCCs a degree is generally preferred if not required. So it will probably be difficult to get past the Regional level without a degree. And I would not count on the requirement for a degree being lifted in the future, even if there are plenty of future retirements at the majors. The fact is, a larger percentage of society has a college degree than ever before; and whether or not it is fair more and more jobs than in the past require them. In this environment, where having a degree is becoming progressively more common, it seems unlikely that a company would stop requiring one. There is an overwhelming amount of competition for jobs at the majors and it is unlikely that the standards will ever be relaxed.
You could always try to make a lifelong career at the regionals, of course, but that is unlikely to work for your entire career with how unstable the regional airline industry is. Your regional could always be shut down like Comair eventually, and then you'd have to start out all over again as a first-year FO at a different regional, if any are even hiring. The regionals will always be unstable as there is a great deal of competition between them to provide regional feed for the lowest price possible. Also the mainline partners create additional instability among them to encourage the regional airline companies themselves to offer lower prices; and to lower operating costs within these regionals.
There are captains at some regionals who have been there for over 20 years and are making decent money, albeit significantly less than a mainline pilot- but understand it is in the best interests of the mainline partner not to allow regional employees to accrue that much longevity. Constantly shifting flying to other regionals and expanding them allows most of it to be done by newer employees who are on the lower part of the pay scale, thereby lowering costs. My employer is expanding right now because of United's use of this strategy, but someday United will shift our flying to a regional that underbids us. That is how the outsourced regional feed industry works.
I actually did get an aviation degree, and I matriculated right after high school. I've often wondered whether it would have been better to get my certificates as quickly as possible, get hired at a regional much sooner than I actually did, and then get an online degree. But people who have done or are doing this seem to recommend against it because of the difficulty of completing a degree while working full-time as a pilot. Since it sounds like you've already made progress toward a degree it would probably be wise to finish it now.