All travelers — even babies — arriving in the U.S. by air must have a passport.

For the third year in a row, the Milwaukee Brewers’ lights-out closer John Axford faced a challenge when it came to getting to spring training on time.

In 2010, it was an auto accident; in 2011 a case of food poisoning. This season it was red tape involving his 8-month-old son, J.B., also known to Axford’s Twitter followers as “Little Ax.” The boy was born in Milwaukee, and is a U.S. citizen.

The elder Axford, however, is a Canadian. And his trip to Arizona was delayed because he didn’t have a passport for the baby when he was planning to fly from Canada into the United States.

His Twitter followers (@JohnAxford) got a play-by-play of his travel travails.

Among the offerings: “Thank you Homeland Security for not letting my AMERICAN son into AMERICA! #3YearValentinesCurse #WontBeSeeingYouTodayWarmWeatherInPhoenix“

He was more expansive in an interview with the Journal Sentinel, which is what prompted us to turn our version of the radar gun — the Truth-O-Meter — on Axford.

“Homeland Security requires passports for every age, no matter what,” Axford said in the interview. “You can arrive by land or sea if you’re under the age of 15 with a birth certificate, but if you go by air Homeland Security requires passports for everybody, no matter what the age.”

Is he right?

Passports only by air, though birth certificates suffice by car or boat?

Now, it’s true Axford is a sports figure. But his statement touches squarely on U.S. policy. So we checked with the State Department, Homeland Security, border control and several federal government websites.

Turns out the rules are different for border-crossing babies, depending on the mode of travel.

If you’re traveling by air, you need a passport. Period.  

And, yes, you have to get a photograph of the kid.

A kid passport costs $105. However, if you’re coming by land — such as the border crossing in Detroit — the rules are less strict, and less expensive.

“U.S. children ages 15 and under arriving by land or sea from a contiguous territory may present an original or copy of his or her birth certificate (issued by the Vital Records Department in the state where he or she was born), a Consular Report of Birth Abroad, or a Naturalization Certificate.  If the child is a newborn and the actual birth certificate has not arrived from the Vital Records Department, we will accept a Hospital issued birth certificate.”

Each year, the federal government issues about 450,000 passports to infants, a spokeswoman for the State Department said in an email. The department even provides helpful hints for how to take a passport picture of your little one.

Kiddie passports are valid for five years.

In the end, Axford got to spring training the hard way, again. His father drove the family across the border to Detroit and they caught a flight from there to Arizona.

Our conclusion

Axford’s trip back to the mound took a detour. He said it was because of travel delays and said federal law required his baby to have a passport to fly back into the country. He learned a valuable lesson about border crossing: The feds are always right.

We rate Axford’s statement True.