One small airline has led the way in the United States when it comes to passenger fees: Spirit Airlines, the no-frills carrier that prides itself for offering the lowest fares, then charging passengers for everything else.

Need an agent to print out a boarding pass at the airport? That’s $10. Want some water? That’s $3. Rolling a bag on board? The tag costs $35 from home and $50 at the airport. In all, there are about 70 fees enumerated in dizzying detail on Spirit’s website for customers to navigate.

To the millions of travelers flying this summer, the fees can be infuriating, but Spirit makes no apologies. In an age of consolidation in the airline industry, Spirit, with about 1 percent of the nation’s passenger traffic, has managed to succeed by going it alone, scraping for every dollar and scrimping on every cost.

“Spirit does everything it can to make or save a buck,” said Henry Harteveldt, a travel analyst with Hudson Crossing. “To its credit, Spirit doesn’t promise passengers that they’ll be coddled. Its customer service standards are terrible, and the airline’s actions have shown it doesn’t care about being liked or respected.”

The driving force behind that strategy is Spirit’s chief executive, Ben Baldanza, 51, an industry veteran who arrived at Spirit eight years ago with no experience at a no-frills airline. Along with an obsessive attention to keeping costs low, Baldanza argues that the cornucopia of fees allows the airline to keep its fares lower than rivals.

Spirit is routinely rated as the nation’s worst airline because some travelers deem the fees unfair. The Transportation Department receives far more complaints about Spirit than other carriers, with six to eight complaints per 100,000 passengers compared with the industry average of 1.4. And Spirit’s on-time record is similarly abysmal, at a 68.8 percent compared with 80 percent for the industry average. The best airlines are in the mid-90s.

Last year, Spirit had its fourth consecutive year of profitability, and generated some of the best returns in the industry.