I got some news the other day that will require me to fly once a week from January until April/May. I have the JetBlue Plus card that I love, but when searching for flights, their routes weren't the most convenient for me but Delta's flights were perfect. I was considering the CSR in February when I am under 5/24 but Delta isn't a UR partner and they have been emailing me for the past few months with a signup offer of 50k points and $50 statement credit. I decided to go for it since I figured that $550 would come in handy. I was approved with $18,700 CL (surprising, since I said I'm a student) and 18.99% APR.
Data points:
- Credit score somewhere around 750-770 (BoA, Barclays and Discover haven't updated my scores yet so that data is about a month old but not much has changed)
- I haven't received a notification about a HP yet so I don't know who they pulled
- I was added to my mom's Hilton Amex in August so I have a young relationship with Amex
- Last app was 9/2/16 for the JetBlue Plus Card
Now to decide if I want to go for an Amtrak card or not 
Fantastic and great timing! Good luck on your travels.