FWIW, I don't think busting an ATP on a weekend course will adversely impact your airline dreams all that much.

You take a Tac Air guy, who has 10, 12, or 20 years of a no hiccups. Then he dingles this check and does a re-do…

What is the biggest concern an airline has about a guy like that? That he can't fly, or that he shows up in class thinking "oh yeah…how hard can it be to fly cross country all the time, especially as as co-pilot…?" Guys who have busted the ATP understand the value of a little humility.

As a more experienced airline pilot now, I understand that learning the 121 (soon 117) way isn't easier, or harder, but it is "different". Airlines need guys with pliant enough attitudes to com in and adapt effectively. Having had their hand caught in a car door on an ATP checkout probably just says "yeah…this guy learned he wasn't ALL THAT, and that whatever you decide to learn to fly you better take it serious…."

I'm not an airline recruiter, but I've had a healthy handful of clients who have had a bad day at All ATPS or or similar places. It didn't' seem to stop them from getting the call, or the job. It sucks to have to say "…well…yes…I HAVE busted an FAA check ride…" instead of "…nope!…" but I don't think its a career killer. Its just a little bit of humble pie you get to eat in front of your interviewers...