Yo don;t say when you are going - and the time of year/weather might make a difference.

If it were me I would look first at the safety record of each before deciding.

Have only done flights in conjunction with river trips, ie, very brief chopper ride from river to Bar-10 ranch for take-out, and fixed wing flight in smallish plane from Bar-10 back to airstrip near Lee's Ferry, maybe 100+ miles over the canyon.

Fixed wing flight was fine so long as you have a window seat. In general chopper flights can go lower (some even land inside the canyon on Hualapai land outside the National Park) and of course hover. I'd expect either would be OK but chopper flight more 'exciting'.

Safety record used to be pretty bad for both fixed wing and chopper flights, with seemingly a crash every other year. Seems to be better the past 10 years (they've limited the flight corridors and tightened up on pilot requirements) but still roughly 400% worse than more conventional air travel. Choppers are more prone to crashes than planes.

It's still more dangerous to drive though.

Basically either trip works fine so long as you have a window seat, I feel.

Thanks. In response to nytraveler, I'm there for 3 nights in end- September. I suppose my main doubt was if the quality of the views we'd get from the airplanes would be much worse than the helicopter (window seats). Airplane trips I've looked at generally seem cheaper. My in-laws have pretty conservative tastes, and 'exciting' is not something they might be too interested in