At American, it's company policy, not contractual.
If the employee dies with less than 15 years of service, the surviving spouse or domestic partner gets travel for 2 years. If the employee dies with 15 years of service or more, then the surviving spouse or DP gets lifetime travel benefits. Also, if the employee dies in the line of duty for the company, the survivor benefits are lifetime, even if the employee had less than 15 years of service.
Travel benefits available in either scenario include:
*D2R (retiree priority) for surviving spouse/DP and eligible children up to 24 years of age, unlimited
*D2P for parents/parents-in-law of the deceased employee, unlimited
*D3 (Buddy pass) travel, controlled/authorized by the spouse/DP, 8 one way passes anually
*A9 (personal emergency travel) for eligible family members, using the same rules as active employees
Essentially, the surviving spouse/DP reverts to retiree travel benefits for 2 years or lifetime, depending on the situation.