President Trump displayed revised plans for his proposed White House ballroom Sunday night on Air Force One, after a New York Times article detailed criticisms that architects and preservationists have made of the design as the project has sped toward construction.

One criticized feature — a grand staircase to the ballroom’s south portico that served no functional purpose — was missing from the new renderings shown by the president.

“We just got these in from the architects,” the president said, walking through a series of printed illustrations while speaking with reporters.

But his impromptu presentation may complicate what is supposed to be a final vote on the project by the National Capital Planning Commission on Thursday. The commission is scheduled to deliberate and vote on plans for the project that were presented at its March monthly meeting. Mr. Trump has now shown, however, that those plans are outdated — or, at minimum, that they’re a moving target.

That may mean his architects will have to return before the panel to explain what they’ve changed before a vote can occur. A spokesman for the commission said its staff was working with the White House to understand any updates that have been made. The commission, composed mostly of the president’s allies, is still expected to approve the project.

As of Monday, no updated plans were available for public review on the commission’s website among materials for the meeting. A last-minute change-up before the commission would be unusual — but also in keeping with how the ballroom has vaulted over the steps by which major public projects in the capital are normally reviewed.

Architects and preservation organizations have warned that little scrutiny has been given to the design plans. They say the ballroom will overwhelm the executive residence in size, alter the White House grounds, and block the symbolic axis between the Capitol and the White House in the 1791 city plan by Pierre Charles L’Enfant.