Cheap Flights from London to Tampa from $333

Regarding the London gatwick flight on British air, I was not assigned a seat until the morning of the flight due to an overbooked flight. Eventually, I got a seat, however, it is anxiety provoking to go to an overbooked overseas flight without a seat assignment. My concern with expedia is that once I book a flight thru expedia is there is no real committment to a customer. It is an attitude of “take your chances with a flight with us”, “you may not get a seat but you paid for the flight”. If I book directly thru an airline, seat assignments are done at booking time. I rarely use expedia due to lack of confidence in having any support from expedia if something goes awry with a flight.