Mayor Michael Bloomberg got a rock star's welcome at Giants Stadium, but is taking some heat for how he made it across the river.

Bloomberg took a helicopter to New Jersey, before driving to the Meadowlands to meet with U2 singer and global activist Bono before the band's concert.

The mayor went directly to the concert after meeting with the president of the Dominican Republic in Washington Heights.

Some are questioning if it was energy efficient of Bloomberg to take the helicopter, but the mayor dismissed the complaints.

"I supposed you could say that, but you know there are other ways to get around, different ways, some are more energy efficient," he said. "I could have walked and swum across the river as well, that would have used less."

The issue did not keep the U2 front man from singing the mayor's praises during the concert.

"He makes me very proud, he also makes me laugh out loud; I love him very much," said Bono. "He's come across the border to see the U2 show in New Jersey. Give it up for Mayor Bloomberg, in the house!"

The mayor has worked with Bono on global issues including diseases and poverty.