Last year for my moose hunt I was nervous about traveling with the pack(k3 with 4800) due to size, length and depth. I bought a 1800 just to shrinking down so only issue was length. Like others I kept all my optics and batteries in it and didn't want to gate check. I also carried a very small collapsible bag that I throw under the seat. Make sure anything you don't want to gate check is easily accessible. That way if forced to, you can throw it all in the small bag and let them check at the gate. I ended up having zero issues. My hunting partner used his 4800 packed to the gills as a carry on and also had no issues. I kind of regret buying the 1800, but better safe than sorry. Good luck.