What Wikipedia says: "Khalifa declined an invitation to tour with rapper Drake and launched his own Waken Baken Tour, a 50-city national tour with rapper Yelawolf." - Wikipedia 

But before you cluck your tongue and think, "What a bad move, you could've been on tour with Drake and learned how to communicate with owls," the Wiki entry goes on to say that Wiz sold out all 50 dates and didn't need the help. Good for him!