I conducted an short, impromptu test on my flight back from Colorado Springs this evening. As I loaded the plane, I was texting several different people to coordinate a ride back to my car from the airport. I took my seat at 7A and received a reply.
As I was conversing back and forth between a potential ride, I noticed that the flight attendant completed her company standard speech about our safety and convenience about flying. I couldn’t remember hearing anything about shutting my mobile phone off, so I continued to send text messages.
After a brief walk-thru, she made her way back to the front of the plane to take her seat. I received and sent another reply on my phone which was hidden from plain view. Our plane began rolling in reverse, away from the hangar and slowly into the tarmac leading to our runway.
I received another text message. The plane turned to the left, then turned left once again. The acceleration swiftly began since we were the one and only plane in line to leave.
I sent one more text message as the plane lifted from the ground before a minute passed with one more received message. We were at least a few hundred feet off the ground when I sent my last text message successfully.
A couple of minutes after the plane ascended to a few thousand feet, I noticed the service bars disappearing. I received no more replies after the last message.
For the next 10 minutes or so, I watched my service bars go in and out. Sometimes they’d be at three bars, sometimes at no bars, sometimes at two bars. Anytime there was more than one bar, seconds later it would go to no bars. The rest of the flight was spotty like this with no chance of there being real service anywhere so I entered my phone into flight mode for the remainder of the flight.
About 10 minutes before landing, I wanted to see if I could once again get service while in the air. I took flight mode off and noticed the same pattern of shifty and sudden drops in bars. It was unlikely that any consistent service was received.
So, that kinda took care of my curiosity about cellular phone usage on flights, confirming what I pretty much assumed anyway.
Here is an experiment similar in nature to my test.