He's known as "Amtrak Joe," but former Vice President Joe Biden's presidential campaign spent a lot more money on private air travel during the third quarter than his top rivals for the 2020 Democratic nomination.
The Biden campaign spent nearly $924,000 on private jet travel in the third quarter, according to data from the Federal Elections Commission. South Bend, Indiana, Mayor Pete Buttigieg's campaign, by comparison, spent $443,000 on private jets.
Biden's big spending on private jets was disclosed in an official campaign finance filing that showed the former vice president's campaign had nearly $9 million in cash on hand heading into the fourth quarter. That put him well behind Sen. Bernie Sanders, Sen. Elizabeth Warren and Buttigieg.
Biden's dwindling fundraising and cash reserves have his donors and fundraisers worried he might not have the resources to make it beyond the Super Tuesday primaries March 3.
FEC records show that the Biden campaign paid EJCR, a company that connected him to private jet services from Virginia-based Advanced Aviation. Advanced Aviation owns and operates campaigntrips.com and is used by other presidential candidates, including Buttigieg and Warren.
Candidates often use private jets to keep up with travel plans around the country while minimizing the time spent traveling. Unlike regular aircraft, private jets are unlikely to be delayed due to baggage loading and other planes running off schedule.
Buttigieg mostly used Advanced Aviation, but he and his campaign also flew using Evojets, Club Jet Charter, and Vertivue Air Charters. The South Bend mayor took home the record for having spent the most on private jets in all of 2019 in July.
Warren spent more than $132,000 on private air travel, and Sanders spent more than $360,000.
Biden's campaign did not reply to a request for comment from CNBC.
The former vice president's "Amtrak Joe" moniker came from his advocacy for cross-country railway improvement and devotion to rail commuting from Delaware to Washington, D.C., when he was a U.S. senator.
Indeed, Biden's campaign did spend $44,000 on Amtrak travel during the quarter – about twice as much as Buttigieg, Sanders and Warren combined in the same time period.
Graphic by CNBC's Nate Rattner