I take mine as a carry-on; I've stored it under the seat and in the overhead compartment depending on how full the compartments are. This might be more than you need to know, but my usual travel set-up is a carry-on-size wheelie bag, a soft bag (i.e., purse) for my laptop and misc. stuff, and my uke in its gig bag. I don't check anything. I cross my fingers and hope that when I get to the gate they'll be inviting gate-checked bags; in that case, I gate-check the suitcase and then I take on the uke and the purse with me to my seat. If they're not gate-checking bags, I take my wallet, charger, book, whatever else, and put it in the gig bag and put the purse into the suitcase. Then I've only got two bags: the gig bag and the suitcase. I put the suitcase in the overhead and have the gig bag by me.
It helps that all of these items are black, as is my coat, so it's possible to get on the airplane with all three items kind of blending into one another and not get busted for having three carry-ons.