The third girl left for her honeymoon in the Caribbean,Mom waited for a week,nothing.Another week went by,and still,nothing.Then,after a whole month,a card finally arrived.Writen on it,in shaky handwriting,were the words:"British Airways".Mom took out her latest Harper`s Bazaar magazine,flipped through the pages,fearing the worst,and finally found the ed for the airline.The ad said:"Three times a day,seven days a week,both ways."Mom fainted

first time i didn't get a joke.. either this joke failed or i don't understnad it..