Steven Slater -- the ex- Jet Blue flight attendant who infamously slid down an airplane evacuation slide after quitting his job last year -- has finally finished his court-mandated mental health treatment.
Slater was sentenced to a year of probation after completing the treatment program, this according to the Queens County D.A.'s office in New York.
As we previously reported, Slater copped to two counts of criminal mischief last year -- and was ordered to pay Jet Blue $10,000 in restitution for the emergency slide.
Slater told CNN, "It's great to see that there is an alternate to hard time for cases that, in my mind, don't necessarily merit hard time. This was a good alternative."
They say imitation is the sincerest form of flattery -- but this weekend,
Steven Slater just had to confront his own imitator face-to-face on a New York City stage.

Everyone's favorite flight attendant took the stage for a brief cameo in "NEWSical the Musical," a comedy that makes fun of current affairs -- and features quite the number mocking Slater.
His appearance is only for a minute or so ... about the time it takes someone to grab a few beers and jump down an emergency slide.
Steven Slater still owes
JetBlue $10,000 for that whole "grabbing two beers and hopping off an airplane via the emergency chute" thing -- and now he has a plan to pay off the tab ... $20 at a time.

Slater is hawkin' Flight 1052-inspired clothing on his website --
StevenSlaterFund.com -- and for $19.99 you get an ironic t-shirt (
above) depicting his most infamous meltdown in stick figure form.
Now you can rest easy this holiday season knowing you've done your part to help a man who will probably disappear from the spotlight forever in the next few months.
Former
JetBlue flight attendant
Steven Slater is now a professional RAPPER -- and TMZ has obtained his new song ... a song that makes
Angelina from "
Jersey Shore" look like friggin'
Jay-Z.

Dude just scored a contract to spit some rhymes for a company called
Line 2 -- a cell phone app that provides in-flight texting ability on airplanes that have Wi-Fi.
As for some of the lyrical gems ...
My name is Steven Slater...And I'm no longer blue...Now don't be a hater...Cause you never flew.Now I'm pimping Line 2... And the killer app it is...My legal fees are paid...By the .com biz.Climb into the cockpit...And throw all the switches...Now you're using Line 2...I'm Steven Slater bitches.
Dope.
Ex-
JetBlue flight attendant
Steven Slater insists he really did get smacked in the head on flight 1052 back in August ... but claims the meltdown was "the perfect storm of bad manners."

Slater appeared on "
Larry King Live" last night ... and for the first time, gave a blow-by-blow description of what he says went down in the moments before he snapped, grabbed two brewskis and jumped down the emergency slide.
Steven Slater's day went from bad to worse yesterday -- because while he was busy
pleading guilty in that whole
JetBlue mess -- his home was allegedly burglarized by his partner's brother.

According to the Queens D.A., 39-year-old
Jonathan Rochelle allegedly broke into Slater's home in Queens by entering through a back window ... and then stole a computer, a printer, and a microwave oven.
Rochelle -- who lives a few blocks from the former flight attendant's home -- was arrested later on Tuesday and is awaiting arraignment on a second-degree burglary charge. The
New York Post first reported the arrest.
We took your questions today on everything -- including
Junior Seau being released from the hospital,
Steven Slater pleading guilty, and
Linday Lohan's probation violation hearing.

Plus:
Magic Johnson sells his 5% stake in the
L.A. Lakers ... from his private jet.
Former
JetBlue flight attendant
Steven Slater just pled guilty to two criminal counts stemming from his onboard meltdown back in August -- and has been ordered to check into a mental health program.

Slater pled guilty to 2 counts of criminal mischief -- but instead of going to jail, Slater worked out a deal where he will have to spend one year in a Queens mental health program. He was also ordered to pay a $10,000 fine upon completing his program.
Not a bad deal -- considering Slater faced seven years behind bars for his post-flight freak-out.
UPDATE: Outside of court, Slater said, "At the end of the day, I am a grown adult, and must accept responsibility for my actions."
Former JetBlue flight attendant
Steven Slater's lips were sealed when we asked him why he flew with
one of JetBlue's competitors yesterday ... but in this case, a look was worth a thousand words.

TMZ spoke with Steven when he arrived at JFK airport, where he did answer questions about his court hearing today -- saying he had his "fingers crossed" ... but believed it was all in "good hands."
We'll be following Steven's court case today -- so stay tuned for updates.
Former
JetBlue flight attendant
Steven Slater is taking his business elsewhere -- dude boarded a non-JetBlue aircraft today ... and no, he wasn't seated anywhere near an emergency exit.

TMZ has obtained photos of Slater catching a
US Airways flight this morning from Charlotte, North Carolina to New York City -- where he's required to appear in Queens County Criminal Court tomorrow over his infamous post-flight meltdown.
As
we previously reported, Slater -- who faces 7 years in prison for charges including reckless endangerment -- agreed to voluntarily admit himself into a
mental health program as part of a possible plea deal.
We'll be covering the case ... so stay tuned.
We took your questions today on everything -- including
Junior Seau getting arrested, released, then driving off a cliff and surviving
,
Justin Bieber being the victim of some homophobic bullying
, and
Oksana Grigorieva landing her 40th lawyer.

Plus: Ex
-JetBlue attendant
Steven Slater takes flight again.