I will never let a laptop be separated from myself. As a last resort, one can place it behind one's back for takeoff and landing if the airline insists on putting the bag in the hold and you have no alternative bag. If I know I'll be a bulkhead seat w/ no floor storage, I pack a minimal bag (actually a pouch) in my carry-on that I place items I will use at my seat into and put behind my back for takeoff and landing. Don't even have to bother with retrieving stuff from overhead.