My advice is as good as what you paid for it:

One thing I have seen over the last 20 years of flying at charter companies, private 91 jets, regional airlines and now at major airlines is planned aircraft deliveries are mostly just empty promises. I wouldn't leave living in base with more than 10% of the pilot group behind me for promises of new airplanes and growth at another airline. These promises can vanish overnight.

I think you need to keep in mind how bad things can get. This is going to make me sound so old but when I was your age I had to walk my resume into multiple flight schools to get them to hire me as a flight instructor. None of the majors were hiring. The job market was ugly. You have to keep in mind that things will get that bad again. Would you rather be in your safe position now and ride out the storm comfortably holding a line and living in base? Or on the street hoping to get your job back at the airline that just cancelled all the aircraft orders you were so excited about?

We are in the "winners curse" phase of the economic cycle. Everything is awesome. This won't last forever. It may be 2-3 years but things will change. Your move would mean maximum risk to your career and your earnings. Put away the max into your 401K, your ROTH IRA and you HSA. I promise you this money will absolutely be life changing in 30 years when you are 56. Think of what happens if you leave Delta and move to UA and are furloughed for this time. You lose out on so much retirement potential. Not to mention day to day pain of unemployment. Are you willing to risk all that? For what? Everyone is different and it is your choice to make but to me leaving a job at Delta for growth at another major seems like a massive risk for very little reward.

Quoted for maximum truth. By the time the OP gets settled into the new job their life could have changed where the flying they want to do may not be important anymore. Instead of barely working and spending time doing what they love they will be on reserve being far removed from what they love and enjoy. There is no way to measure this or quantify it but it is so, so important.

they say Youth is wasted on the young. This thread proves that 😂. Joking of course but you have 1500 people behind you at the worlds most profitable airline. If you live in base stay put. Either way, enjoy the long career at either.

^^^ this ^^^ my only caveat is if you want to be based in a city with a large domicile at United that doesn’t exist for DAL… then I’d switch in a heartbeat for QoL and take the possible hit to your end game seniority.

This ^^^ AMEN.

If the OP had an additional truly compelling reason for making the leap, that could tip the scales. For example, a strong need or desire to move to SFO might be a good reason. But NONE of the other WB bases can match SFO's WB flying. IAH WB flying arguably sucks (except for guys with girlfriends south of the border), and even East Coast WB is not all that compared to SFO. Plus, IAH is a comparatively senior base to boot. If the OP had only been on property a couple of months, that would be one thing but with 1500 already behind you and lots of retirements coming rain or shine... stay put, you'll have a great career at DAL.

Free advice (you get what you pay for). Stay. Last bid went senior, most junior NB captain/ WB FO was 5000 or so from the bottom, and I really think that is going to be the norm. Yes they are planning on hiring. But that is not guranteed. From the Hogan to a class date will be at least 8 months, so by that time you will have less above and more below at DL. You will definitely not get WBFO/NBCA faster going to UAL.

Leave DAL for UAL 1.5 years/1500 below living in base? In my situation (Live in base, rarely look forward to locations that I fly, bid min credit max day off, don't want to go through probation again etc.) probably not. DAL work rules and soft pay are very similar to UALs with some better reserve, premium pay and commuter rules. Even with UALs and DALs profit sharing formula are now the same, the first year DAL pilots were paid more due to DAL making more money than UAL IIRC.

Since you're young and want to fly to all of these international destinations yourself... It might make sense for you.

You obviously applied to UAL for a reason. Take the Hogan, interview, get the CJO and then see what your thoughts are when you get your class date.

You want to leave DL, where you already have a year and a half of seniority and longevity, for another Legacy carrier not because of commuting/base reasons but because of Krazy Kirby’s ridiculous growth plans? Am I reading this right?

Yeah, good luck with that.

Delta takes back pilots who leave them for another airline, even a competing legacy? How generous of them.