There are still a number of signs on New York state highways warning drivers that their speed may be watched by air craft in the skies, but this is simply not the case. The New York State Police say they could use the planes in this manner if they chose to do so, but since they have not done since in almost a decade, and the price of jet fuel has greatly increased since then, it seems unlikely they will do so any time soon.
However, just because they are not patrolling the skies watching for speeders does not mean New York drivers can speed with impunity. In fact, states such as New York have come to rely on the revenue generated by traffic citations, which makes speeders an easy target. Police can and do use an assortment of tools to monitor the speed of traffic including radar guns and automated traffic control devices. They do not even need to use automated devices or lasers, and can instead simply judge your speed using a simple mathematical formula for determining your speed.
In the end, how fast you are going is a subjective matter determined by the police who are watching you. If you go to court you will need something other than your word against the word of the police officer if you expect to escape your fine. Judges will always side with the police, accepting their word over the word of anyone regardless of whether or not there is any evidence to support their claim.