Russia's invasion of Ukraine has added another obstacle for air cargo-reliant supply chains already challenged by climbing rates and limited capacity.

Airlines large and small have adjusted their operations to minimize the war's impact, leading many to cancel services and flights to Ukraine and Russia as early as Feb. 24, when the attack began. The two countries are also home to fleets that specialize in handling extra-large cargo, which are hard to find elsewhere.

Commercial flights have vanished from the skies of Ukraine and surrounding areas as carriers avoid the conflict's airspace. Rerouted flights and climbing fuel costs have resulted in higher surcharges for shippers and further flight cancellations as some services between Europe and Asia became economically unviable for carriers. This has happened during a period of already limited cargo space, as the COVID-19 pandemic grounded many aircraft due to plummeting passenger demand.

"With the crisis in Ukraine now, we're sort of back to those early days of the pandemic because lots of capacity has been sidelined," Neel Jones Shah, Flexport's executive vice president and global head of airfreight, said earlier this month.

Some air cargo carriers are still traveling freely through Russian airspace. Airplanes for China Southern and Air China were doing so on Wednesday afternoon, per Flightradar24. But at least 11 of the world's top 25 cargo airlines, according to the International Air Transport Association's (IATA) 2020 rankings, and smaller operators have made some sort of adjustment due to the war.

Here is a rundown of those changes. Included in the list for most carriers is 2020 data from IATA on cargo tonne-kilometers (CTK) flown, a measure of cargo activity. This list will be updated regularly.