That's not 4% from current flying. Its 4% from future published schedule, which is more than it is currently. This was clarified after the filing by Nocella when he was asked about it specifically. Obviously we have new hire classes still running and scheduled to continue. If we were cutting 4% from current, they would probably stop hiring for the rest of the year.

Quote from an interview...

The company is planning to cut capacity as a result of slowing economic growth. Chief commercial officer Andrew Nocella says it intends to reduce utilisation of its narrowbody by roughly 2% in coming quarters, ”effectively lowering our domestic capacity by two points”, he says.

Its only "domestic capacity" being reduced but international will still grow as we've announce new routes and new 787s are being delivered.

Also they said on the earnings call that Basic Economy is bringing in more revenue than expected and they plan to offer more tickets at that price level to stimulate demand.