They won't run out of tier 1 for a very long time. Last source of inside info from over there is they still have a conglomerate of apps that meet and exceed their standards. Another interesting concept is tier 1 never gets depleted. They keep rolling tier 2 apps to tier 1. Two years ago Delta said they had 600 tier 1 apps, but 12,000 on file. Two years later they have hired over 2k. It seems to be a system when they score apps that are competitive and then those apps are dumped into tier 1. Kind of like a collector tank on an rj .