There are several reasons why your Delta SkyMiles may not be appearing in your account after a flight in 2026. The most common reason is a name mismatch; the name on your ticket must exactly match the name on your SkyMiles account. If you booked through a third-party site or travel agent, your SkyMiles number might not have been properly attached to the reservation. Additionally, certain deeply discounted fares or "Basic Economy" tickets on partner airlines may not be eligible for mileage accrual. It typically takes 24 hours for Delta flights and up to 7 days for partner flights to post. If it has been more than a week, you should log into your account and use the "Request Mileage Credit" tool. Ensure you have your 13-digit ticket number (starting with 006) and your boarding pass handy. Note that you must have been a member at the time of travel, although Delta occasionally allows new members to claim credit for flights taken up to 30 days prior to enrollment.