Using a laptop while on a long flight is perhaps the only way one can stay sane. Unfortunately for owners of Dell and Apple laptops, Virgin Atlantic has seen it fit to impose a ban on those laptops, or at least the batteries they carry. Should you bring one on board, you'll be forced to remove the battery from it and rely on the in-flight power. Even though a recall is taking place and the number of affected models is very small, the batteries, manufactured by Sony, just aren't being trusted. If you aren't lucky enough to be on a flight with power plugs and you don't have a different brand laptop, you're just out of luck.
Virgin Atlantic says they are in communication with Apple and Dell, and will lift the ban in the future, once the battery recall issue is completely resolved. But of course, that could be never.