I didn’t think you could do it, however I hid a small portable space furnace in my suitcase as well! When they x-rayed the suitcase and found the space heater, I had to go back to the main part of the airport and have the bag checked in and put in with the other luggage… Then I had absolutely no need for the space furnace on the plane and I could not plug it in, so I didn’t think what all the furor was about! The people I was with and I were finally on the airplane and getting ready to take flight when I tried to turn on the heat vent. It was frigid in the plane and I asked the flight attendant about the ongoing heat. She said it would turn on when the people I was with and I were in the air. I had a six-hour flight, and I was hoping the plane would get into the air before I froze to death… My sweater was overhead, and I was simply cold. I could believe my bones aching from shivering, and I wasn’t the only one. I heard several children yelling they were cold, and I could see some older people who were uncomfortable. I grumbled about having a space heater, and the flight attendant heard me. She said they had some small furnaces you could put on the footrest, but they could not be used until they were at full altitude. By that time, I was going to be a popsicle. I was getting to where I could repeat her words about being at full altitude before they could turn any heat on, right along with her as well… And after about twenty five hours, I could believe heat pouring out of the air vents.