The Bernie Sanders campaign spent just under $1.2 million on private jet travel last quarter, outpacing the entire 2020 Democratic presidential primary field.

The most recent filing from Sanders reveals $1,199,579 in spending during the final three months of 2019 to Apollo Jets, LLC, a "luxury private jet charter service." The campaign spent an additional $23,941 for transportation to Virginia-based Advanced Aviation Team.

The candidate who comes closest to matching Sanders in private jet spending was former vice president Joe Biden, whose campaign spent $1,040,698 to Advanced Aviation Team last quarter.

An analysis of private jet spending in filings from other top candidates found that Elizabeth Warren's campaign spent $720,518 and Pete Buttigieg's campaign spent $323,518. Michael Bloomberg, who pumped a whopping $200 million of his personal fortune into his campaign's opening weeks, spent about $646,000 on private jet travel, about half of what Sanders spent.

Sanders has long leaned on private air travel on the campaign trail, despite his belief that limiting carbon emissions from the transportation sector is crucial to combating climate change. Traveling by private jet is estimated to produce roughly eight times the amount of carbon per passenger as traveling by commercial airliner.

"Global climate change is real, it is caused mainly by emissions released from burning fossil fuels and it poses a catastrophic threat to the long-term longevity of our planet," he writes on his campaign website. "The transportation sector accounts for about 26 percent of carbon pollution emissions."

Sanders further claims on his website that "climate change is the single greatest threat facing our planet."

The Sanders campaign has reportedly stepped up its use of private jet travel in recent weeks, chartering flights to get him back and forth between his duties in the U.S. Senate and the campaign trail in Iowa.

The Sanders campaign had previously spent about $380,000 on private air travel, also with Apollo Jets, LLC, according to previous campaign disclosures.

The Sanders campaign says the environmental impact of its private jet use is mitigated by the purchase of carbon offsets, which it purchases from NativeEnergy. Entering the final quarter of 2019, the Sanders campaign had purchased $9,030 worth of carbon offsets. It purchased an additional $23,200 in carbon offsets from NativeEnergy this past quarter, the most recent filing shows.

Alternatively, Amtrak offers service from D.C. to Iowa, which would cost Sanders $149 using the senior discount.

UPDATE 11:00 p.m.: This piece has been updated with additional information on carbon offset purchases.