Boeing may apply for special permits to flight-test modifications and operate production flight-test and ferry flights of newly assembled 737 Max aircraft in U.S. airspace during the as-yet-indefinite worldwide commercial-flight ban affecting all 737 Max-family jets, the U.S. Federal Aviation Administration confirmed Thursday.

“The order allows for ferry and repositioning flights under certain conditions,” one FAA spokesperson told AIN, while another subsequently confirmed that “Boeing may apply for a special flight permit to reposition aircraft for storage.”

Close reading of the emergency grounding order issued by the FAA on Wednesday shows the order specifically provides for the FAA potentially to allow such flights. “Special flight permits may be issued in accordance with 14 CPR. 21.197 and 21.199, including to allow non-passenger carrying flights, as needed, for purposes of flight to a base for storage, production flight testing, repairs, alterations, or maintenance,” the order’s second page reads. “Experimental airworthiness certificates may be issued in accordance with 14 CPR 21.191 to support certification of design changes.”

Lack of aircraft parking space at Boeing’s facility at Renton—where all 737s undergo final assembly—and at the immediately adjacent Renton Municipal Airport, from which all 737s make their first flights, could make the capability to operate such flights important to Boeing if the 737 Max grounding continues for more than two or three weeks. “Boeing has paused delivery of 737 Max airplanes due to the temporary grounding,” said Boeing in a statement released Thursday afternoon. “We continue to build 737 Max airplanes, while assessing how the situation, including potential capacity constraints, will impact our production system.”

However, the Boeing 737 assembly facility and Renton Municipal Airport—which is only 170 acres in area—together offer enough parking space for fewer than thirty 737-size aircraft. Boeing now assembles new 737s—mainly 737 Max variants but also some 737NGs as production gradually transitions to the new Max family—at a rate of 52 aircraft a month and expects to increase the rate to 57 a month later this year, meaning the available aircraft parking space at the Renton complex amounts to no more than about two weeks of current 737 production. Should both the 737 Max grounding and assembly of new aircraft continue for much longer than two weeks, Boeing will need to find storage locations elsewhere and therefore fly them out of Renton.

Separately, UK-based aviation technical consultancy IBA Group yesterday released an estimate that each grounded 737 Max aircraft costs its airline operator up to $150,000 a day in otherwise unabsorbed direct costs: $12,000 a day in rental payment or mortgage interest, $5,000 in staff costs, $5,000 in airport parking fees, $100,000 in re-routing and compensating passengers, and variable amounts in accommodating stranded aircrews and assorted engineering and maintenance costs. In many cases the lost opportunity cost of revenue the airline cannot generate from each grounded aircraft will amount to even more than $150,000, according to IBA Group—and possibly as much as $75,000 for every 737 Max flight not operated.