CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Millions	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
Cash flows from operating activities:
Net Income	$ 103.0	$ 63.9
Adjustments to reconcile net income to net cash provided by operating activites:
Fleet transition costs - CRJ-700	36.9	3.4
Depreciation and amortization	122.0	114.2
Stock-based Compensation	7.3	8.7
Increase in air traffic liability	172.1	162.7
Decrease in other assets and liabilities – net	(72.6)	(19.3)
Net cash provided by operating activities	368.7	333.6
Cash flows from investing activities:
Aircraft and aircraft purchase deposits	(214.8)	(45.3)
Other flight equipment	(11.1)	(52.6)
Other property and equipment	(15.2)	(13.9)
Total property and equipment additions	(241.1)	(111.8)
Proceeds from disposition of assets	12.4	3.3
Purchases of marketable securities	(427.7)	(578.1)
Sales and maturities of marketable securities	459.0	446.2
Increase in receivable related to Terminal 6 at LAX airport	(44.6)	0
Restricted deposits and other	0.1	0.5
Net cash used in investing activities	(241.9)	(239.9)
Cash flows from financing activities:
Long-term debt payments	(125.4)	(130.9)
Purchase of treasury stock	(33.3)	(26.3)
Proceeds and tax benefit from issuance of common stock	14.9	21.0
Other financing activities	(5.5)	(13.6)
Net cash used in financing activities	(149.3)	(149.8)
Net change in cash and cash equivalents	(22.5)	(56.1)
Cash and cash equivalents at beginning of year	89.5	164.2
Cash and cash equivalents at end of period	67.0	108.1
Supplemental disclosure of cash paid during the period for:
Interest (net of amount capitalized)	39.7	47.5
Income taxes	$ 0.1	$ (4.8)