If you don’t yet have an Alaska Airlines (IATA: AS) account, click this link to register for a Mileage Plan account by the end of April, and then take one AS flight by the end of September to receive 5,000 bonus miles. Alaska Airlines miles are quite valuable: 12,500 miles are enough for a one-way domestic award ticket within the U.S. with one stopover. So if you expect to fly AS soon, don’t miss this opportunity.