Boeing didn't receive new orders for jets in July, delivered four commercial planes and removed 52 backlogged orders for the grounded 737 MAX, according to the company.

The numbers underscored the collapse in demand for air travel since the novel coronavirus pandemic hit earlier this year.

"(Boeing) delivered only four aircraft in July vs. 10 in June and our July estimate of 17," said Cai Rumohr, an analyst at Cowen & Co, in a research note.

"Customer deferrals remain the key issue as customers push out accepting 787 deliveries given international travel remains depressed."

In July, Boeing delivered four wide-body jets: a 767 freighter for FedEx, a 777 freighter for DHL and two 787-9 passenger planes — one for Air France and the other for Turkish Airlines.

Despite a slight uptick in air travel earlier this summer, the collapse in demand for flying means carriers and leasing companies have more planes than needed and therefore have deferred or canceled orders for new aircraft.

The MAX's firm backlog has declined by 864 planes this year, including 416 cancelations and 448 orders removed because the order status is uncertain amid the harsh economic outlook for airlines during the pandemic.

Through July, Boeing had back orders for 3,498 MAXs.

Last month, airlines canceled orders for 43 MAX jets. Another nine orders were removed from the back-order list because the customer's financial situation made it unlikely the aircraft would be delivered and therefore the contracts didn't meet US accounting standards.

Meanwhile, Boeing's European rival Airbus received four new orders in July and delivered 49 planes, including two A220s and 47 A320neos — the main competitor for the MAX.

Earlier this month, the US Federal Aviation Administration announced a proposal for design changes in the 737 MAX and revised pilot training procedures that could lead to the plane being returned to service in the US by the end of the year. But foreign regulators also must approve the plane's updates before allowing it to enter their airspace.

"We continue to make steady progress towards safely returning the airplane to service," Boeing said in a statement.

The MAX, Boeing's best-selling jet, has been grounded worldwide since March 2019 following crashes in Indonesia and Ethiopia that killed a total of 346 passengers and crew.