I’ve done both United & Delta. Currently flying for United. The United stuff is done in Denver, not Chicago (not that it matters … ), and the hogan is the psychometric test. Done at home, not Denver.
Spirit applicants, being ALPA members, get ‘distressed carrier’ consideration (it’s in our contract), but they still go through the full UA process. Delta does online psychometric stuff too (Cut-E test) & a remote interview with a shrink (MMPI) at the end of the assessment day. All going well, you get your CJO & a cheesy pic in front of the Delta Pilot Recruitment sign for your Insta; United makes you wait.