This excerpt taken from the BA 10-K filed Feb 28, 2005.
Purchase obligations Purchase obligations represent contractual agreements to purchase goods or services that are legally binding; specify a fixed, minimum or range of quantities; specify a fixed, minimum, variable, or indexed price provision; and approximate timing of the transaction. In addition, the agreements are not cancelable without a substantial penalty. Long-term debt, capital leases, and operating leases are shown in the above table regardless of whether they meet the characteristics of purchase obligations. Purchase obligations include both amounts that are and are not recorded on the statements of financial position. Approximately 23% of the purchase obligation amounts disclosed above are reimbursable to us pursuant to cost-type government contracts.