Airports are emerging as the next battlefield in the ongoing turf war between cab companies and upstart online firms that connect drivers and riders. Houston officials, perhaps seeing this fight coming, included specific rules keeping drivers for companies like Uber and Lyft out of passenger airports in its revisions to the city taxi and limousine ordinance.

On Wednesday, the City Council will discuss the proposed changes to Houston’s vehicle-for-hire rules, and as Tuesday’s story explained, the alterations specify locations where permits are required to pick up or drop off passengers.

Changes to the taxi and limo laws also would forbid Uber and Lyft drivers from soliciting rides through means other than their online systems, and would ban them from cab stands “near any passenger depot, hotel, airport, ship or ferry landing, bus stop or station.” Rules regarding commercial use of Houston’s passenger airports mean drivers for Uber and Lyft cannot pick up or drop off passengers without a city permit. Cab and limo companies, as well as airport shuttles, pay for annual permits to come to the airport, and also pay a per-trip fee. Each driver would have to decide whether to pay $325 for the permit and $2 per-trip fees to accept airport trips.

Airport trips are an important part of local taxi business, and as Uber’s own map of its travel patterns in the Houston area shows, it was also a popular drop-off and pick-up spot for the on-demand rides as well.

Houston is not the only city where the new entrants are being discouraged, by permit requirements, from serving airports. San Francisco and Chicago are both trying to keep them out as well, for the same reason Houston is telling them to stay away: Permits and fees related to airport trips.

In all cases, the airports are huge revenue engines for the cities, which treat the airports as quasi-governmental entities that operate under a board of commissioners. With so many taxis, shuttles and others using the airports to make money, the airports take a cut by requiring permits. Ideally, that means roads are improved and the airport is designed with huge taxi and shuttle demand in mind. The permits and fees are nothing new, and they’re similar in their setup to the paid parking common at airports.

Should the fees and permits change as the nature of paid trips change? That’s certainly part of the debate. Lately, however, the focus has been on the new entrants barging into markets and then waiting for the rules to be sorted out later. That’s drawn companies like Uber and Lyft some unwanted attention. In fact, it’s gotten so heated in San Francisco the airport’s director has said many of the drivers for the new entrants are violating California law.

If that happens in Houston, there will be tough penalties, including possible impounding of vehicles found in violation. Councilman Michael Kubosh, who has repeatedly said the new companies should have to meet the same standards as taxis for a “level playing field” if they want to do business, said he was still hesitant to authorize such a severe penalty for a single offense. Kubosh said someone who didn’t have proof of valid insurance in the vehicle could then lose it and pay tow fees, even if they could come to court later and prove they had insurance.

“They say you could get the money back,” Kubosh said. “But how often do you hear anyone getting that money back from tow companies?”