WestJet today announced it is updating the number of carry-on pieces guests are permitted to bring on board to one from two, plus one personal item, effective 4/4/13 The carry-on item (eg. a suitcase, backpack or bag) must be no larger than 21 inches by 9 inches by 15 inches and it must fit in the WestJet sizing devices located in airports across our network. If it does not fit, it must be checked at the boarding gate and picked up upon arrival at the baggage carousel.