ATLANTA (AP) -- Aviation observers say the death of Delta Air Lines' partner Comair was a result of high fuel costs that made its 50-seat regional jets too expensive to fly, and high labor costs that made it difficult to compete with other small carriers.

The weekend brought the final flight for Comair, a subsidiary of Atlanta-based Delta that flew under the Delta Connection brand.

The Atlanta Journal-Constitution reports Comair's last flight also marked the end for an industry pioneer that helped spearhead the introduction of the 50-seat regional jets that replaced most turboprops in the 1990's.

Delta says it expects no service disruptions, because other Delta Connection regional carriers are taking over flights.

Erlanger-based Comair's 1,700 employees will be laid off, including about 30 Georgia-based pilots and flight attendants.