Its more than $4B to buy Virgin America because of the debt that was assumed.

"Under the deal, Alaska Air will pay $57 in cash per Virgin share. Virgin closed Friday at $38.90. The companies described the entire value of the deal at about $4 billion, including debt and aircraft leases."

Estimated Total Cost for Virgin America at $4B

This under no circumstances seems like a good deal. What did they pay for exactly? This sounds like they are trying to spin a stupid decision into something beneficial.