Big Time Rush

"Big Time Rush" lead singer Kendall Schmidt is having issues with the airlines again after his custom made guitar was destroyed in flight ... and he demands American Airlines pony up.

Kendall had an appearance in Sacramento Sunday where he was supposed to perform ... but showed up with a mangled piece of wood instead of the $4,000 guitar he bought 6 months ago.

And Kendall says American isn't making things easy ... informing him he shouldn't expect any answers for at least a month.

American has a liability limitation of $3,400 for domestic flights ... so, best case scenario, he'd be out $600 ... unless he got insurance.

Kendall's had other airline woes ... he says a bag with $7,000 in jewelry went missing last year.

We've reached out to American ... but they must have lost our number.

Big Time Rush singer Kendall Schmidt is a generous man -- paying off a $243 ticket some random female fan got while speeding to his concert -- but there's no such thing as a free lunch ... and Kendall wants some big things in return.

Sources close to Kendall tell TMZ, a girl emailed the singer this week, claiming she got the speeding ticket in Rochester, NY, while hauling ass to a show for Kendall's side band Heffron Drive.

The girl said she's a broke college student and couldn't afford to pay it ... so she begged Kendall for some financial help.

According to sources, Kendall agreed to pay the ticket on the condition she graduate with a 3.0 GPA minimum. He's also asking her to volunteer 20 hours of her time to benefit her community.

He's not joking either -- we're told Kendall plans to follow up with the girl regularly to keep her honest.

Former Nickelodeon boy band star James Maslow no longer looks like Donny Osmond's stunt double ... these days he could nearly pass for Captain America.

Maslow's transformation in the last year is unbelievable ... going from some 70s mop-haired baby-faced cheeseball to a Chris Evans look-alike in a matter of months.

A good move ... especially if he wants to keep getting jobs in Hollywood ... and not at some Atlantic City variety show.

The biggest danger for a boy band ... girls.

Big Time Rush bandmates Kendall and Logan insisted on camera (above) their group is not breaking up ... but sources familiar with the situation tell TMZ ... the band is getting Yoko'd.

Here's what's happening. Carlos just got engaged, and his fiancee is demanding that he spend more time with her -- away from the group. She feels he's not pulling his weight in the wedding-planning department, and Carlos is feeling the pressure.

James has been dating a chick who is making similar time demands. We're told they're in a "committed relationship" and she feels he's been MIA way too much.

Short story ... Kendall (who's also in the band, Heffron Drive) and Logan are trying to put a good face on things, but there's Big Time trouble.

"Big Time Rush" lead singer Kendall Schmidt has taken the phrase "man's best friend" to a whole new level -- by tattooing the face of his dog Sissy on his back ... and TMZ has the photographic proof.

Sources close to Sissy -- Kendall's adorable Boston Terrier -- tell TMZ ... the singer immortalized the pooch's mug onto the left side of his back a few weeks ago at Smith Street Tattoo in Brooklyn.

We're told the ink job took about an hour and was pretty painful -- but it won't be his last ... especially if he ever gets another dog.

​Members of squeaky-clean Nickelodeon boy band Big Time Rush are banging like bunnies ... at least that's what they strongly suggested to our photog.

Our guy innocently asked Kendall Schmidt if the band would consider a reality show. He laughed hard ... and then worried out loud that their fan base would not approve of their lifestyle.

What happens when you fall off your bike in a gnarly motorcycle crash? YOU GET YOUR ASS BACK ON ... especially if you're "Big Time Rush" star Logan Henderson.

TMZ has learned ... the Nickelodeon actor is back up on two wheels after a frightening crash in Hollywood back in December that he luckily escaped from with only scrapes and bruises.

Henderson's motorcycle was badly damaged in the wreck -- when he was cut off by another driver and thrown from his bike. But Henderson was determined to ride again ... and had the bike repaired.

The final bill -- $8,000 ... but luckily for Logan, we're told the other driver's insurance covered the cost.

After the repairs, Logan was so pumped to get back on his bike -- he rode it to set for the taping of the season 3 finale of "BTR" ... and don't worry, he made it there safely.

Kendall Schmidt from "Big Time Rush" tried to do a nice thing for his fans in Europe ... but says he got screwed when the airlines lost his bag, and thousands of dollars worth of jewelry.

Schmidt -- BTR's lead singer on the TV show, and in the band -- is currently performing with his other band, Heffron Drive, on a European tour ... and wanted to give his fans some custom-made necklaces and bracelets.

According to our sources, Schmidt was flying from Orlando to Austria when the bag filled with the jewelry went missing.

We're told the luggage eventually resurfaced in Berlin, but the $7,000 worth of goodies had disappeared. We're told Schmidt filed a report with the airline ... in hopes of getting a cash reimbursement.

At least Schmidt was able to joke about it during his show in Vienna.

"Big Time Rush" star Logan Henderson was in a nasty motorcycle wreck last week ... and might've James Dean-ed himself into the history books ... if not for a lucky jacket he was wearing ... TMZ has learned.

According to sources, the Nickelodeon boy bander was cruising through the Hollywood and Vine intersection on his way to the studio ... when a car turned right in front of him.

Henderson swerved at the last second to avoid an accident ... and was violently chucked off his bike in the process.

Remarkably, he was able to stand afterwards ... scraped and bruised from frisbeeing across the blacktop ... but still alive, we're told, thanks in part to his Marc Jacobs jacket ... which he claims saved his back from becoming a mangled mess.

The accident understandably put the kibosh on his trip to the studio ... but Henderson's gonna be just fine.

His bike, on the other hand? Not so much -- it's in the shop for the foreseeable future.

"Big Time Rush" lead singer Kendall Schmidt is so popular with the ladies ... he plunked down some major dough and moved all the way to Sin City to escape some love-crazed female fans ... TMZ has learned.

Sources close to Kendall tell TMZ ... several members of Kendall's team became concerned after some overzealous fans began camping outside of the 22-year-old's L.A. pad ... and they urged him to get another place where he could hide out.

We're told Kendall took the note and quickly found a place in Las Vegas -- inside a well-protected gated community.

Here are the stats -- 1,900 square feet, 3 beds, 3 baths ... and it cost somewhere between $300k and $400k.

We're told Kendall still owns his place in L.A. -- and will use the home when he comes to town -- but the Vegas pad will be his primary residence.