The city's largest network of charter schools is stepping up its campaign for middle school space in Queens, gathering thousands of its students and their parents for a rally.

The Success Academy says fourth graders at four of its Queens elementary schools may have to leave its network if the city does not provide adequate space for a middle school. Students and parents say that's not fair.

"Mayor de Blasio should do something about that. Because he had to go to school to become the mayor, so why would he want to take away others’ chances to become mayor?" said one student.

The charter network gave its students in Queens half the day off for the rally, and provided buses to take them there.

The network and its founder, Eva Moskowitz, have staged such protests through the years to pressure Mayor de Blasio for more space.

"It's not exactly a tactic. I'm not an elected official. I can't wave my wand. The only thing we have is to advocate and to beg and plead and to ask the politicians to do the right thing," said Moskowitz.

De Blasio is no fan of charters, which are publicly funded but privately run and he has had issues with Moskowitz in the past.

The Success Academy boasts high tests scores and long waiting lists, but de Blasio and other critics have claimed the network is too focused on test prep.  And yet, a state law requires the city to pay the rent for charters if it won't provide them public space and Schools Chancellor Richard Carranza said this week the students would get their middle school.

“To those families, I’m going to say you’re going to have your middle school,” said Carranza. “Wherever those spaces are, we have to have a conversation with those school communities as well as the charter community, and parents in those charter communities.”

Moskowitz says she's heard that promise before and wants to share information with parents ahead of the December 2nd deadline to apply to district middle schools.

"I don't want to be jaded, but when you keep making promises and you don't deliver on them, it leads to a certain level of skepticism,” said Moskowitz. “Maybe they do have one. But time is, tick-tock, time is running out."

New York City’s Education Department says it will meet with Success about middle school space on October 8th.