WASHINGTON — Senators have reached a compromise to dramatically increase the number of flight hours new commercial copilots need to get a license, though the figure falls short of what the group Families of Continental Flight 3407 was seeking. Under a deal brokered by Sen. Charles E. Schumer and announced Friday, new co-pilots would have to have 800 hours of flight experience in specific, rigorous conditions, up from the current 250 hours of general experience.