I completely agree with the above poster. I work in planning/zoning and I know that our local ordinance does not require a special/conditional use permit for airstrips in the agricultural district (after reading your post I may need to propose some ordinance changes). Call your local planning dept and ask them if they know anything about the proposal and what is the process. Give them your name and number and ask them to contact you if they recieve any applications for that type of use on the property.
If a special or conditional use permit is required, NC law requires that nearby/adjacent property owners must be notified, a public hearing must be held, and there are four findings a board has to make in order to issue the permit. If they apply for one, you need to look at those four findings and base your argument against the airstrip based on the findings. One finding is that the use is in harmony with the area around it...this may be a good point for you to address. Another has something to do with that it will negatively affect the property values of the surroundng area. In order to prove this, you must have an appraiser (or maybe even a real estate agent) testify that property values would negatively be affected. Just your word against the applicant's isn't enough. Also, the board has the authority to place conditions on the use (hours of operation, the use cannot be within X feet of another property or structure, etc).
Anyhow, your first step would be to touch base with the planning dept and find out if the use requires a special/conditional use permit. If it is just a permitted use, and it does not require a public hearing, you may want to consider applying for a text amendment to amend the ordinance to require one (or convince the local planner that there is a need for it and they may propose it). You may also want to contact a Commissioner and convince them that it is a bad idea before an application is submitted (you are not allowed to contact them about the issue once the SUP/CUP application has been submitted).
Another thing to remember, in case this issue does end with a public hearing, boards tend to count heads when reviewing an application. If you come in with a bunch of people that are opposed to this proposal then you stand a much stronger chance of them turning it down then if it is just you against the buyer, real estate agent, and current owner.
Hopefully, the real estate agent was honest with you and the buyer has decided it is a bad idea (but I really would
not take his word for it). If the buyer is going through the trouble of talking to neighboring owners, then I would think he is pretty serious about the property.
Finally, I don't blame you for being very concerned about the prospect of an airstrip near your property. I think there are valid concerns that need to be addressed, and most reasonable people would be concerned about the noise, traffic, fumes, etc. that may be generated from this type of use near their home.