It can be remote but shifted in time. E.g. send a remote command that essentially says "if in airplane mode, every 60 minutes turn radio on and check for new commands".

That would cause major issues in areas where phones are forbidden for national security or sensitive equipment reasons from having antennas active. I've never heard a report that a manufacturer has even considered that idea as it could potentially cost them major damages.

Of course, that's not something that a legitimate manufacturer would have in their standard firmware.

However, that is a possibility for specific malicious firmware uploaded to some "phone of interest" to prevent its user from protecting themselves by turning on airplane mode.