I'm trying to save battery but I need my alarm in the morning. Will it still go off if on airplane mode?
p.s. I have an HTC Inspire.
Yes. Airplane mode (flight mode) only disables your phone's signal transmitting functions, not the functions that don't require a signal to function.
Your alarm will still work.
As @Jasir says. Your alarm will still work in Airplane mode.
Be careful as there is another setting on your phone.
Clock > Alarms > Menu > Settings > 'Alarm in silent mode'
You will need this ticked if you put your phone in silent (saving more battery) and still want the alarm to go off!
Do a quick, simple test on your phone (that's what I did):
Put your phone on airplane mode, then set an alarm for 1 (one) minute into the future. If done correctly, your alarm should sound off within 1 minute. Then you know it works!
Alarm clock requires no Internet connection.
So yes, alarm is still on with airplane/flight mode enabled
Actually your phone time needs to occasionally access the network's time server to stay synced and that might affect your alarm. I didnt wake up today because i set an alarm for 3 hrs, set airplane mode, and it never rang, but i can't really prove this now.