2016 Accord. August 2020 oil change at Honda San Antonio dealer 52031 miles. Shop checklist said air filter OK. A couple of weeks later, I looked at the engine compartment and the filter clips are flapping so I muttered and clipped them tight.
June 2021 oil change at Corpus Christi dealer 58,691 miles. Service writer came to see me in the waiting area and informed me there was no air filter. Blew top then calmed down.
I don't recall being on anything but pavement but traveled through wind and rain. Car seems to be running OK
but
1) what should I have inspected if anything?
2) is there a secondary filter someplace in there that might save my neck?
nope there's only one filter.
Stick a boroscope down the spark plug holes and inspect cylinder walls for scoring.
Welcome to dealership incompetent service. Go find a good, independent mechanic.