The charter flights, which originate in Texas, have been underway since at least August, according to the New York Post.
Two planes reportedly landed at Westchester County airport last week, and, according to Post reporters who viewed the landing, most passengers appeared to be children and teens, with a few appearing to be men in their 20s.
Recent flights reportedly landed at 10:49 pm on Wednesday and 9:52 pm on Friday, where county cops stood by as passengers were loaded onto buses.
Some passengers later met up with relatives or sponsors in New Jersey, or were dropped off at a residential facility on Long Island.
Around 2,000 migrants have reportedly landed at the Westchester County airport on 21 flights since August 8. Some flights have arrived between midnight and 6:30 am, when a voluntary curfew is in place.
A source familiar with the operation told the Post that the underage migrants are bused to locations that include the Bronx, Brooklyn, Queens, or upstate Newburgh, as well as Bridgeport and Danbury in Connecticut.
The Friday night flight stopped in Syosset, Long Island at around 12:30 am on Saturday, where the campus of MercyFirst is located.
MercyFirst is run by the Catholic Sisters of Mercy, which provides housing and services for "children and adolescents who are the victims of societal problems." MercyFirst reportedly has a contract to supply the federal government with residential services for "immigrant youth."
One bus on Friday night left the airport, traveling down the Hutchinson River Parkway, which is off limits to commercial vehicles, at speeds which exceeded 75 mph before crossing the Throgs Neck Bridge.
On Wednesday, two buses were viewed leaving the Westchester airport with around 100 passengers, who had arrived on a McDonnell Douglas MD-83.
One of these busses stopped at the Thomas Edison Service Area on the New Jersey Turnpike in Woodbridge. Migrants left the bus at around 12:45 am on Thursday.
The migrants were then driven away by people over the next two hours from the service area, "without anyone appearing to have to show identification to the officials overseeing the operation," the Post reported.
On Saturday, in a similar fashion to other flights on their way to Westchester, a flight landed in Jacksonville, Florida at around 10 pm, where between 10 to 15 people wearing matching white baseball caps and carrying duffel bags were let off the flight as local cops stood by.
This group of migrants was dropped off Twin Oaks Academy, a juvenile detention center near Tallahassee, at around 1 am on Sunday.
When presented with the New York Post's findings, Republican Florida Gov. Ron DeSantis expressed outrage, with a spokeswoman saying "if the Biden Administration is so confident that their open-border policy is good for our country, why the secrecy?"
"Why is the Biden Administration refusing to share even the most basic information about illegal alien resettlement in communities throughout our state and the entire country?" said Florida spokeswoman Christina Pushaw.
"Washington, DC, sets immigration policies that do not affect them, and states — that lack information about migrant resettlement and do not have the authority to change federal immigration policy — are expected to bear the brunt of Biden's reckless open-borders agenda," she continued.
The White House said on Monday that only children and teens are carried on these flights. The US Department of Health and Human Services said, "It is our legal responsibility to safely care for unaccompanied children until they can be swiftly unified with a parent or a vetted sponsor."
"Our Office of Refugee Resettlement facilitates travel for the children in its custody to their family or sponsors across the country," said HHS spokesman Jorge Silva.
"In recent weeks, unaccompanied children passed through the Westchester airport en route to their final destination to be unified with their parents or vetted sponsor," he continued.
The Biden administration has had a policy since taking office of allowing unaccompanied migrant children to enter the US with essentially no questions asked.
Their Build Back Better plan contained a provision for mass amnesty for migrants who are already in the US. This was denied as a legislative measure by the Senate parliamentarian, who said that this kind of law could not be passed as part of a spending bill.