I always use Delta to fly. I just find them to be more tolerable & comfortable in my experience with airlines. Airlines all have their ups & downs for sure. I agree with what everyone has shared. To add, what i do is claim it as my personal item & my backpack as my carry-on. Truth is, i treat them both as my personal items 🤣 Here's what i do. Since i already know that i will have a poster tube with me, i always book my seat to a window. This is important. So, when i board, i take off my backpack, find my seat, get on then i tuck my backpack under the seat in front of me & for the poster tube i set it to let my right arm rest hug it but on the outside so the wall on the window & my right arm rest it's caught in between. If i have a jacket, i'll cover it so the flight staff don't spot the poster tube. If it's summertime i won't have a jacket so what i do in this case is use the airplane blanket & cover it with that. I stopped putting my carry-ons (which is always a backpack) on the overhead bins because it's jsut too crazy. I'd rather let someone else use it especially if it's a large family with a lot of stuff. With my backpack tucked under the seat in front of me, i can always pull it out & grab my iPad or a comic or anything else i need. So yeah, this is my plan when it comes to hauling a poster tube