I've never had any trouble using mine in flight. American Airlines doesn't specifically prohibit it in their list of unapproved electronic devices, and nobody has ever asked me to turn it off in flight. I have used it on many flights with AA since getting it in December, ranging from flights as short as ORD-IND to flights as long as MIA-LAX. I'm planning on using it this afternoon, too, as I head from LAX-BOS. It's especially great if you're in a seat with a power port, because those GPS's use too much battery power on a long flight!