Just did some research on airfares between a couple of different cities for the Thanksgiving holidays. I found that unrestricted coach fares are exactly the same as First Class fares. Is that always the case, even in non-holiday periods? What on earth is the justification for that?

only business fliers (not paying their own way) and people in a crunch (short notice, gotta fly regardless of the cost) typically pay these fares; unrestricted coach fares are also fully changeable without penalty, so the airline can incur some hassles while holding the reservation.
first class on many domestic flights is a colossal waste of $$ (though a nice option if obtained by FFM's or bump-upgrade); most coast to coast flights are better, but compared to overseas first class accommodations, domestic first just isn't much better than coach.
by the way, if you check fares too far advance, sometimes they haven't been brought into competitive range yet

Hey Jerome, I work for UA and if you do end up purchasing a coach ticket for anywhere near the 1st class at time of check in see a ticket agent and ask if there are any seats in 1st for you. Point out that you paid big bucks for the ticket. I do agree and also disagree with helle the short flights are not worth it but the long hauls the cushiony seat make the world of difference and the service is totally different better food ( if any of it is good? lol) and more one on one service.Happy flying!!!!!

Sally-For someone who supposedly works for an airline, you sure have been posting alot here lately! Makes me wonder if you really do work for UA. Why don't you do us all a favor and get a life baby! OR better yet, let the real travelers post here.

What are you yammering about, MM?
So what you're saying is that people who work for airlines aren't "real travellers"? What's that supposed to mean? many people who work for airlines choose to do so BECAUSE they love to travel and they get great perks that way. And many people who work for airlines get large chunks of time off, which might allow them to read these forums, contribute to HELP OTHERS, or just learn for themselves.
Get a life yourself, MM. Isn't school back in session yet?

This was a legit question and Sally's answer was helpful. MM a.k.a xxx is a grouch with a bad attitude who should mind his manners and quit following Sally around to pester her. (If Sally's been working on Apollo computers for most of her career, she can probably type in her comments in about the time it takes MM/xxx to think of his real name.)