Airlines love charging travelers for checking their bags, which can add hundreds of dollars to the cost of travel for families. Delta may be considering breaking from the pack, and is testing a policy that would waive checked-bag fees for select passengers in an effort to keep them from overloading carry-on space and delaying departures. But the tests are limited to one airport, Boston, and it remains to be seen if the change will go nationwide, let alone spread to other airlines. In the meantime, we're still stuck cramming everything into our carry-ons to avoid fees. Here are packing tips and tricks that can help.