hi there-i'm looking to travel from JFK to LHR on 11/29, and returning on 12/3. do you know if there is a blackout for travel in December & January? i remember my mother-in-law (retired flight attendant) mentioning that at some point... and i don't want to bother asking her for buddy passes if i wouldn't be able to travel on those dates anyway.thanks in advance, for any blackout info that you can provide...cheers,nicole