SCOTT AIR FORCE BASE, ILLINOIS (NYTIMES) - In a room dimly lit by television screens, dozens of airmen tapped away at computers and worked the phones.
Some were keeping watch over a high-priority mission to move a Russian-made Mi-17 helicopter from a base in Arizona to a destination near Ukraine's border.
Earlier that day, a civilian colleague had checked a spreadsheet and found a C-17 transport plane in Washington state that was available to pick up the helicopter and begin a daylong trip.
It was up to the airmen to give the plane's crew its orders, make sure the plane took off and landed on time and handle any problems along the way.
The C-17 would fly from McChord Air Force Base near Tacoma, Washington, to Davis-Monthan Air Force Base outside Tucson, Arizona, where the helicopter was parked in a repository for retired military airplanes known as "the boneyard."
"So it's 2 1/2 hours from McChord to Davis-Monthan," said Col. Bob Buente, reviewing the first leg of the journey.
"Then four hours to load. Then they'll take off about 7:30 tonight. Then five hours to Bangor. Then we'll put them to bed because of the size of the next leg."
From Bangor, Maine, the cargo flight - call sign: Reach 140 - would leave for Europe, the colonel said.
Since the war in Ukraine began four months ago, the Biden administration has contributed billions of dollars in military aid to the Ukrainian government, including US-made machine guns, howitzers and artillery rocket launchers, as well as Russian-designed weaponry that the country's military still uses, like the Mi-17 helicopter.
The Pentagon has drawn many of the items from its own inventory.
But how they reach Ukraine often involves behind-the-scenes coordination by teams at a military base in Illinois, about 25 miles east of St. Louis.
There at Scott Air Force Base, where a half-dozen retired transport planes are on display just outside the main gate, several thousand logisticians from each branch of the armed forces work at the US Transportation Command - or Transcom.
In military parlance, it is a "combatant command," equal to better-known units that are responsible for parts of the globe - like Central Command and Indo-Pacific Command - and takes its orders directly from the secretary of defence.
Transcom has worked out the flow of every shipment of military aid from the United States to Ukraine, which began in August and kicked into high gear after the Russian invasion.
The process begins when the government in Kyiv, Ukraine, sends a request to a call centre on a US base in Stuttgart, Germany, where a coalition of more than 40 nations coordinates the aid.
Some of the orders are filled by a US partner or ally, and the rest are handled by the United States - routed through US European Command, which is also in Stuttgart, to Defence Secretary Lloyd J. Austin III and Gen. Mark A. Milley, chair of the Joint Chiefs of Staff, who discuss them in weekly meetings with the service chiefs and combatant commanders.
If the desired items are available and the combatant commanders decide that giving them to Ukraine will not unduly harm their own war plans, Gen. Milley makes a recommendation to Mr Austin, who in turn makes a recommendation to President Joe Biden.
If the President signs off, Transcom figures out how to move the aid to an airfield or port near Ukraine.
The order to move the Russian helicopter zipped across the base in Illinois from Transcom's headquarters to a one-story brick building housing the 618th Air Operations Centre, where red-lit clocks offered the local time at major military aviation bases in California, Alaska, Hawaii, Japan, Qatar and Germany.
Col Buente runs the day-to-day operations at the 618th Air Operations Centre, where about 850 active-duty airmen, reservists and civilians spend their days planning missions like the helicopter's trip, he said.
Making sure those plans are carried out falls to a smaller group - working in shifts of 60 people, 24 hours a day, every day of the year - that follows the stream of missions posted on a constantly updated screen centered on the back wall all the way to completion.
It is the same centre that orchestrated the mass evacuation of Americans and Afghans from Afghanistan's capital in August.
On the busiest day then, 21,000 passengers were flown out of the Kabul airport, with planes taking off or landing every 90 minutes, officials said.
Mr Biden authorised the first US military equipment and weapons for Ukraine - a US$60 million package - on August 27.
It took about a month to get those items onto planes after they were approved, according to Mr Van Ovost, a test pilot who flew cargo planes.
The White House has announced 13 subsequent aid packages for Ukraine, and the planning process has advanced enough that it now takes less than a day from the president approving a shipment to having the first items loaded onto a plane, she said.