couric: good evening, everyone. the ill familiar roar of jet engines was met with applause across northern europe today as flight restrictions were finally eased. all british airports were reopened this weekend, more than five days after that giant plume of volcanic ash from iceland forced them to shut down. and about three quarters of the continent is now free of flight restrictions. this view during a two-hour period this evening shows much of europe back up and flying. but there s still a big bottleneck of travelers all over the world. mark phillips is at london s heathrow airport. mark, they must be breathing a lot easier there tonight. reporter: yes, katie, indeed. there was a strange sight throughout this past evening: airplanes actually landing. airports across europe and the u.k. have begun to reopen and with the erratic behavior of that volcano in iceland, this has been a dramatic day of false starts. love you, baby. reporter: colleen louw stuck in london tal