The debut of Amazon’s next-day package delivery on Oahu last month was made possible by a new late-night flight that extends the order cutoff window for shoppers, an Amazon spokesperson confirmed.

Amazon (NASDAQ: AMZN) opened a delivery station in Honolulu more than a year ago and was bringing in packages twice a day from the U.S. mainland using two widebody jets that belong to its private cargo airline. Most of the 3.5 million packages delivered so far took at least two days to reach customers. Amazon recently added another flight that departs the continental U.S. at a later time, allowing it to offer a later cutoff window for loading outbound shipments and still meet its next-day promise, Hawai’i Public Radio reported.

The A330-300 aircraft being used, which were converted from passenger configuration before entering service with Amazon, are operated by Alaska Airlines. Hawaiian Airlines originally had the contract to support Amazon’s air network, but it was acquired by Alaska Air last year. This week the airlines received a single operating certificate from the Federal Aviation Administration allowing for the integration of training, policies, procedures and manuals. Amazon isn’t certified to fly its own aircraft.

Various airports support the Honolulu flights, including bases in California and the company’s main hub at Cincinnati-Northern Kentucky International Airport, according to online flight tracking data.

A local Amazon manager told the news outlet that the Honolulu operation has exceeded expectations for the first year of service and expanding to next-day delivery happened faster than anticipated.

Meanwhile, Amazon’s one-year-old wholesale air cargo business that sells excess airfreight capacity to third-party shippers, is moving thousands of Maui Gold pineapples from the state to the mainland every week in under 12 hours, local TV station KHON2 reported in September. Much of the unused space Amazon offers on Amazon Air flights is on backhaul flights to logistics hubs, which are mostly empty because Amazon operate a one-way, B2C parcel shipping network

In July, Air Premia, a passenger airline based in South Korea, entered into a transportation services agreement with Amazon Air Cargo under which it transfers belly cargo to Amazon at Honolulu airport for onward carriage to the continental United States. Once at U.S. hubs, the Air Premia shipments are relayed to 45 cities, including Atlanta and Houston, through the Amazon Air network.

Amazon Air Cargo also offers service to Columbia and the Dominican Republic. Avianca Cargo, the cargo division of Columbia-based passenger airline Avianca, is booking shipments on Amazon flights returning to the U.S.