This excerpt taken from the AYR 8-K filed Sep 26, 2007.
Share-Based Payment. We use the straight line method of accounting for compensation cost on share based payment awards that contain pro-rata vesting provisions. Prior to our initial public offering, the fair value of the equity instruments was determined based on a valuation which took into account various assumptions that were subjective. Such assumptions involved projecting our earnings through the date of the anticipated initial public offering to develop an estimated annualized rate of earnings and annualized earnings and dividends per share. Key assumptions used in developing the projection included expected monthly acquisition volume through the date of the initial public offering, leverage and interest costs, revenues from new aircraft acquisitions and the growth of selling, general and administrative expenses. Compensation costs relating to share based payments recognized subsequent to the initial public offering are measured based upon the market price of our common shares at the grant date. We anticipate that the current requisite service periods will be obtained for employees with awards.