I used the Trtl for a long time but found it incompatible with wearing a mask on the plane (which, I'm never going back - filter N95s for life when I fly, I get sick so much less from traveling now!). Anyway, I switched to the pillow I'll link below and love it. I'm a side sleeper and this feels the most like sleeping on my side that I've been able to replicate while flying.

https://www.amazon.com/Travelrest-Ultimate-Travel-Pillow-Neck/dp/B001DYDAEK/ref=mp_s_a_1_4?