The St. Petersburg-Tampa Airboat Line began flying across Tampa Bay on January 1, 1914. It lasted only three months.
The flight covered 20 kilometers (18 miles) and took 23 minutes-11 hours less than travelling between St. Petersburg and Tampa by rail.
The Airboat Line safely transported 1,204 passengers across the bay. But without continuing subsidy from St. Petersburg or steady income from tourist traffic, it could not survive. The airline closed at the end of March.
Credit to: https://www.wired.com/