Yep, he's the guy with the airport named after him in New York. He also thought Prohibition was a terrible idea and testified about it before the Senate in 1926. He probably had the best line about Prohibition when he opened his testimony by saying "It is impossible to tell whether prohibition is a good thing or a bad thing. It has never been enforced in this country" (source).

LaGuardia's beef was primarily that Prohibition didn't prevent drinking and it encouraged corruption: treasury agents driving around in private chauffeured limousines, for example. A billion dollars a year was lost to the government in taxes. Speakeasies, pool rooms, and even hat shops were selling alcohol. The government was colluding with criminals by printing bills in denominations of $10,000. Now who would deal in $10,000 bills except bootleggers and gangsters? Fiorello LaGuardia wants to know.

LaGuardia thought it was crazy to let temperance organizations be the ones to evaluate the effects of Prohibition. He called for the government to establish a commission to investigate. The speech was full of impressive statistics, for which he gave no evidence. LaGuardia was correct in that Prohibition had the effect of both increasing corruption and violent crime.

Seriously, though: cite your sources.