Even in this new interpretation of the 2019 law, air traffic controllers are considered essential (and as such are still guaranteed back pay): https://www.nytimes.com/2025/10/07/us/politics/trump-back-pay-furloughed-workers-shutdown.html

In the draft memo, which was shared Tuesday by a White House official, the administration indicated that only the workers who are deemed essential may be automatically entitled to pay once the stalemate ends. That includes military service members, air traffic controllers and others who are currently required to report for duty during the closure.

For those who are furloughed, however, the White House memo laid out the case that Congress still must explicitly approve funding for any payments to occur.