Effective January 2011, Midwest Miles will expire in 24 months if there is no earning or redeeming activity in a member’s account. Until then, miles will not expire unless a member does not earn or redeem miles for 36 months. Frontier EarlyReturns miles are valid for 24 months and the expiration policy change of Midwest Miles is one more step on the way to integrating the two programs, which is expected to be completed in the fall of 2010.