The U.S. will extend slot waivers at New York JFK, LaGuardia and Washington National through October. United, Delta, and American asked for this jointly, to protect their turf without actually having to fly full schedules.
Among other reasons for agreeing, the FAA cites “global vaccination rates” as well as “continued unpredictability of [international] travel restrictions” and “the disparity between demand for domestic air travel and demand for international air travel” despite the fact that only one of the three slot-controlled airports in the U.S. (New York JFK) carries much international traffic at all.