Press Release TORONTO — It was a whirlwind 12 months for airline acquisition news. And it all started with one particularly surprising week in May. On May 13 WestJet announced that it had entered into a definitive agreement for its acquisition by Onex Corporation for an all-cash deal worth $5 billion. On May 16, three days later, Air Canada and Transat said they were in negotiations, with the upshot that Air Canada was looking to buy Transat for some $520…