Trump, a Republican who admired flashy displays of national pride and military strength put on by France, has dismissed concerns about the expense and militaristic overtones of the Washington event, which will take place in front of the Lincoln Memorial and feature fireworks, a flyover by Air Force One and a display of tanks, reports Reuters.

Democrats charge the president with staging a campaign rally. Though the White House has said his remarks would not be political in nature, the president has a history of veering off script with sharp partisan attacks even at events that are not meant to be overtly political.

“People are coming from far and wide to join us today and tonight for what is turning out to be one of the biggest celebrations in the history of our Country,” Trump tweeted on Thursday morning.

He is set to give a speech at 6:30 p.m. ET (2230 GMT), followed by fireworks later in the evening. Asked earlier this week if he could give a speech that would represent all Americans, he said he thought he could and then launched into an attack on Democrats’ policies on healthcare and taxes.

Flights will be suspended at nearby Reagan National Airport from 6:15 p.m. to 7:45 p.m. ET (2215 to 2345 GMT) and then again later in the evening for the festivities.

“Perhaps even Air Force One will do a low & loud sprint over the crowd,” Trump tweeted, encouraging people to get there early.

Some at the White House were worried about the crowd size, according to an administration official. Trump fumed about reports in 2017 that the crowd at his inauguration ceremony on the National Mall in front of the U.S. Capitol was smaller than it was for President Barack Obama. The Lincoln Memorial is at the opposite end of the monument-covered Mall.

Republican political groups were given prime tickets for Trump’s speech, and the Washington Post reported that the U.S. National Park Service diverted $2.5 million in park entrance fees to help pay for the event.

“Instead of addressing something like veteran homelessness, he’s spending it on boosting his ego with a parade that’s fundamentally about him and then getting tickets in the hands of wealthy donors for the Republican Party. What a waste of money,” Democratic presidential candidate Julian Castro said on CBS “This Morning” on Wednesday.

Fellow Democratic presidential candidate Senator Bernie Sanders also weighed in with criticism: “This is what authoritarians do: @realDonaldTrump is taking $2.5 million away from our National Park Service to glorify himself with a spectacle of military tanks rolling through Washington,” he wrote in a tweet.

Trump downplayed the expense.

“The cost of our great Salute to America tomorrow will be very little compared to what it is worth. We own the planes, we have the pilots, the airport is right next door (Andrews), all we need is the fuel,” he posted on Twitter on Wednesday. “We own the tanks and all. Fireworks are donated by two of the greats. Nice!” Andrews is the name of a nearby military base.

The July 4th holiday celebrates the U.S. founders’ declaring independence from Britain in 1776.