McAllen (United States) (AFP) - It will be the first time on a plane for most of the undocumented families that arrive daily at the McAllen, Texas airport, holding envelopes that read "Please help me, I don't speak English."

The envelopes are not passports per se, but might as well be: Inside are the families' boarding passes and negative Covid tests -- everything they need to continue onward on their long journeys fleeing their home countries.

After risking their lives to travel hundreds of miles (kilometers) by bus, car, trailer and on foot, trekking dangerous routes controlled by drug traffickers, and crossing the Rio Grande River, they have finally arrived in the United States.

Everything is new for the dozens of families who come to the airport daily and mostly hail from rural areas: English, airplanes and even the escalator are novelties.

At least for the moment the sky is quite literally the limit as they wait to board their planes to go stay with relatives ahead of their immigration court dates.

'There was no other option'

"We're flying in the clouds!" shouts four-year-old Isaac from Honduras, nose pressed to the window, as the plane takes off from the southeast Texas border city. "I want to touch them."

His mother, Lidia, is on the final stretch of her long journey to reunite with her husband and eldest son, age six, whom she has not seen in two years. 

"It will be the happiest moment of my life to see my son again," the 23-year-old said as she waited near the boarding gate to Houston for the first leg of their flight. 

"We had to separate to find a better future for our children. There was no other option," she said, citing hunger, poverty and violence in Honduras. 

Her husband will not be at the Newark airport to pick her up -- he is undocumented and fears arrest, so will send a friend to retrieve his family. 

Lidia and her son were detained by US Customs and Border Protection (CBP) agents after crossing the Rio Grande near McAllen. Like other immigrants, she was held for several days while they took her fingerprints and recorded her contact information, before being taken for a Covid-19 test. 

Then, like many families, she was released. She and her son walked to a Catholic shelter, the Humanitarian Respite Center, where she waited for her husband to send the plane tickets -- with the shelter providing the envelopes that migrants take to the airport.

Within the next 60 days she is required to report to an Immigration and Customs Enforcement office near her final destination for her hearing "or face removal from the US," according to a document border agents provided her.

Some 100,000 undocumented immigrants were detained by CBP in February alone after crossing the 1,950-miles border with Mexico, a number not seen since mid-2019 before the coronavirus pandemic. The official numbers for March, authorities say, will be even higher.

US President Joe Biden's administration has warned that the border is not open, but he is not deporting the increasing number of minors who arrive alone nor separating families with children, in contrast with his predecessor Donald Trump.

'The plane is a pleasure'

Dania, a 24-year-old Honduran woman also traveling with a child, said she had gone "through very difficult times in Mexico. We were hungry, sleep-deprived, it was exhausting and sometimes risky."

Migrants report the worst part of the trip can be crowded, unventilated trailers.

"We spent 16 hours in a trailer with 200 people, the men all standing in the front, sweating profusely, sometimes shouting out that they were dying, that they were passing out, and water was thrown on them," one Honduran mother said. Now, she is traveling by plane for the first time.

Valeriano, a Guatemalan who grew corn and beans back home, is about to board a flight to New York with his six-year-old son.

Four years ago, members of a cartel killed his bother after he refused to sell drugs, Valeriano said through tears. The cartel wanted to recruit him as well.

"I fled to Belize. They told me they would kill me if I didn't leave, that they would kill my children."

"Our trip was terrible," he said. "Now, the plane is a pleasure, even if I am a little nervous and am afraid of heights."

Arriving at LaGuardia Airport in New York, Dania, the 24-year-old Honduran, and her child were greeted by her husband, Samuel. The family hugged, and the father picked up his son excitedly.

"Later, we will go buy whatever you want," he said with a smile.