You have seen the signs, especially in rural areas where the roads seem endless and remote: "State Police aircraft used in speed enforcement." The signs aren't going away, but the threat is increasingly empty as many state budgets cut back on tracking speeders by air.

In New York State, no tickets have been issued from aircraft since 2005. Sgt. Kern Swoboda, spokesman for the New York State Police, says the planes are still in the police fleet, but paying for pilots and fuel wasn't paying off in revenue so the planes haven't gone up this year.

California has cut way back on using its aircraft for speeders too. The California Highway Patrol still has 15 planes used to catch speeders, but spokeswoman Fran Clader said that as the department's annual air operations budget has dropped from about $12 million to $8 million, aircraft became more focused on supporting searches and pursuits. Washington State is another that has cut way back on speed monitoring pilots.

The Virginia State Police launched an aggressive aerial speed enforcement program in 2000 but largely abandoned regular patrols after 2007. Last year, it flew only one such mission, which resulted in tickets being given to 20 drivers, the department said. It flew four missions the year before, none in 2009 and only one in 2008.

"Due to economic conditions and mandated budget cuts ... we've had to look at cost savings," said department spokeswoman Corinne Geller.

Geller said the cost of aerial speed monitoring by plane costs about $150 per hour -- a figure that includes fuel and maintenance but not manpower. In the past, she said, the speed enforcement flights were paid for with federal grants. But with less federal money coming in lately, resources have been focused on keeping troopers on the road.

Two states bucking the trend and continuing to rack up summons revenue with planes without cutting back are Ohio and Florida. Last year, the Ohio State Highway Patrol said it issued more than 16,000 speeding tickets based on aircraft observations, down only a little from a five-year high of 18,000 written in 2009. Over the Memorial Day weekend, the start of the busy summer travel season, the agency had 10 aircraft in the air doing traffic enforcement.

Florida's Highway Patrol has eight aircraft and eight pilots, who issue approximately 30,000 citations per year.

Even with drastically reduced aerial patrols in some states, the signs remain on the highway and tend to serve as a deterrent on their own. When drivers see the signs warning of aerial, or radar, monitoring, it reflexively causes them to check their speed and adjust downward to avoid getting a ticket.

Signs without planes in the air tend to do some good in getting drivers to slow down, and thus improve public safety. But states don't get the violation revenue if the pilots are not relaying the information to cops to hand out the tickets.

Best advice

Stay within five or six miles per hour of the speed limit and employ a radar detector except in places where they are illegal: Washington DC and Virginia, plus on all military bases.

The Associated Press contributed to this report.