I noticed with airplane mode it disables the cellular signal ie. you can’t connect to a tower.
It does not, however, turn off the radio power. You can check this yourself by entering *#*#4636#*#* into the stock dialer.
Tap,on phone information V2
and see that the cellular radio is still scanning and broadcasting.
You need to manually power off the mobile radio power using the toggle and use airplane mode.
This has been happening for some time.
Pixel 9. Build 2026012801
Using an app,called Network survey provides these results.
Using only airplane mode :

Using only the mobile radio power toggle

Vastly different results.
Using adb I can also see these related global settings:
airplane_mode_radios=cell,bluetooth,uwb,wifi,wimax cdma_cell_broadcast_sms=0 cell_on=0 enable_cellular_on_boot=0I did manually change the on_boot to 0 because it would turn back on even with airplane on.

