I was hoping to garner some objective opinions (let's assume there's no contradiction in terms for a moment), on which career is "better".

I'm an older guy (45) getting back into aviation after having spent 12 years in the maritime industry. I'm leaning towards part 135 and corporate aviation. First of all, there's no age 65 rule in Part 135. I just passed my ATPw on July 31... so even if I do decide to go 121, I won't be subjected to this ridiculous, baffooning requirement of "ATP Certification Training Program", because as of today I only need to accumulate 285 more hours of flying time to reach 1500 total and take the practical. Doing that in two years time will be no problem.

I understand this is an interesting time in the business... it seems as though no one is really sure what is going to happen yet... only speculation.

That being said, could someone correct me if I'm wrong in saying that a Part 135 career potentially offers way more flexibility, and way better pay (at least in the beginning)? I've compared entry level salaries and man... 121 carriers still suck... BIG TIME. I'm too old to get to a major at this point... at least to a position as captain, or in a widebody, or with much seniority. So if I attempt to go just as far as I possibly can (including the possibility of management e.g. CP or DO someday), which route would you take if you were in my tired old shoes?

Unless you're starstruck for being a regional captain one day then forget the airlines. FO pay is terrible, competition is fierce, quality of life is poor, few make it to mainline, and the economic future is uncertain at most regionals. I'm pushing 50 and the idea of being a regional FO the way the job is now is not very appealing to me. We do have a few late middle-age career changers on the forums who seem to like the life, though.

"Unless you're starstruck for being a regional captain one day then forget the airlines. FO pay is terrible, competition is fierce, quality of life is poor..."

...and with the dismal reality that regionals are probably going to have to fork out money to help new hires reach 1500 hours if they want to avoid cancelling flights (i.e. Horizon Air), I'd expect pay at regionals to REMAIN horrible. What a circus... unless one is a very young pilot who has a large financial backing, and being a doormat for 10 years is acceptable with the prospect of getting that diamond major airline job someday... then I fail to see why people would do this to themselves.

What about Part 135 pilots going directly to the majors while bypassing regionals? Is this a common practice anymore? Say I work at a freight hauler and accumulate 5000 PIC turbine hours... better yet say I get lucky and accumulate 500 jet hours in a Citation? Will the majors be interested in that, or will they "poo-poo-you-don't-have-part 121-experience" me?

I can only report what rumors I hear and read, but getting to mainline through corporate/135 is not common unless you already have prior 121 history. Going the other way is more common and from what I can tell, corporate/135 companies hold 121 applicants in high regard perhaps because they know 121 is competitive and the flying is demanding.

As for why newly made pilots still flock to the regionals only to take a beating for years on end, the debate goes on here daily. I think that once a person decides to do the airline flying it becomes very hard to change course, and the relevant demographic also seems to suffer from poor research skills and a tendency not to study it thoroughly before deciding. A decision is made early on, and there may be an unusual amount of hubris involved. Like in many things, career preference and individual mentality seem to go together.

You can still have a decent career at the big boys at this age, forget the regionals.
It's possible to be hitting 6 figures on third year fo pay and beyond and factor in the retirement contributions it can be lucrative.
Don't know much about 135, I believe scheduled 135 has an age limit.

By working at the regionals for 10 years first? What major hires without prior military and/or airline experience? I would not advise anyone to go to a regional at age 50 to think they are going anywhere but a regional for the rest of their life or most of it.

So you're saying that the big boys practice direct hiring of Part 135 captains, right? Because according to Cub Driver, this doesn't really happen... maybe at some foreign carriers or contract airlines yes, but not U.S. legacy airlines.

Sorry, I don't define a "decent career" as working the last 10 years of my career at a legacy airline flying as F/O out of SLC in an MD88, every gosh dang Christmas and Thanksgiving. Just saying.

I wouldn't give up on 121 just yet. Yes, the last 14 years have been rough in the 121 world, but HUGE retirement numbers are looming. The next 10 years won't be like the last 10.

I've worked at 2 part 135 outfits and 2 part 121, and 121 wins hands down FOR ME (ymmv).

You can make it out of the regionals in a lot less than 10 years.

A few regional pilots make it to the majors??? Please provide stats on that. This is not true.

What do you define as a decent career? As simple as it sounds, that may answer your question. Lots of variety (read: good, bad, or ugly) in the 91/135 world. Much less variety and unknowns in 121. You'll either like 121 or you won't. Some corporate and/or charter jobs may be great. I suspect a good deal more may have some objectionable aspects (short notice on-call, working holidays and higher starting pay that ends up paying the same as a regional by year 4).

The good news is you don't have to pick. Try one for a couple years and if you don't like it, try the other.