You’ll exp. faster seniority initially at UA until 2041. At DL you’ll realize the same seniority progression in 2052.

You’ll enjoy - at its apex but most of the time less - a 9% boost in seniority at UA for for 26 years.. after that it’s a push… 9% is important up until about 70-80% system seniority due to being above furlough line and being a NB CA or WB FO. After that 1-9% is pretty negligible over those 26 yrs. when you factor in the multiple hubs/fleets DL/UA has.

Of course, all of that can change if Delta or United alters their growth plans or another black swan event.

United is flashy with their growth news and likes to take stabs at their competitors (mostly @AA) which I like. Big orders that stem numerous years out, has an outlier 350 order, BoomJets, E-Jets, & BlendedWing orders.. TK was telling NH’s ~30K pilots in 2030-ish. Lots of stuff to be excited about obviously but generally it’s grossly over estimated. But, gamble big win big.. or lose big.

Delta is hyper conservative and shares absolutely zero growth plans. The conservative approach is boring, but DL management prints money (love hate relationship with this strategy). United clearly has more WB’s if that’s your thing. You’ll fly em’ at both though. Global Scope addition in 2023 from DALPA killed the trope of DL giving away WB jobs - now all partner flying DL will have to match 1:1 on TPAC/TATL/South America flying.

DL flies 2 CA on WB’s too vs 3FO1CA and no “relief pilot” only positions. I’d wager Delta’s soft pay rules and ability to “roll thunder” via green slips fairly being distributed to junior pilots makes UA having more WB’s a push.

Ultimately, at your age and ability to live anywhere it’s a more or less the same. Obviously, DL@ATL and UA@DEN have training center opportunity. JFK/LGA & EWR are junior obviously.

Or, accept the first CJO.. I probably should’ve just said that it’s the best plan.