I've been painting airplanes of every size since 1989. The question you ask is unanswerable without further information such as the specific requirements of the regulatory environment in which the facility is located and the types of aircraft you will be painting. At the outset I can confidently state that there will be few if any significant cost differences noted between using low voc (low means like say 3.5lbs/Gal) versus conventional high voc (5.0 and up) coatings.
The only reason then to use lvocc is that the local regulatory body demands it in response to the local air quality issues. Here in Florida, we have no air quality issues with respect to photochemical smog so that for the foreseeable future, there are no voc regulations for refinishers.
Lvocc have the potential to reduce labor costs associated with the application of the coating via the simple expedient of reducing the number of coats required to acheive a given film build. This is partially offset by the higher cost of the coating. If a very high gloss and level appearance is required then the labor savings may be further offset by the additional costs associated with spray equipment capable of delivering such performance with lvocc. You will find that conventional air-atomize spray equipment, and most especially hvlp variants, are incapable of delivering high performance with lvocc. Personnel will then be tempted to add additional viscosity reducers (thereby negating the voc rating) to acheive the desired appearance.
The most availing equipment for lvocc seems to be air-assisted airless atomization using high pressure pumps, prefferably with electrostatic sprayers. Controlled heating of the admix immediately prior to application is also an excellent solution. This latter option is attractive since it can be adapted to any existing application system.
Disposal costs for lvocc should be nearly identical to conventional coatings. Anyway these costs have little to do with voc content of the coating; the knowlege and experience of the crew are the determining factors for waste paint and solvent.
Often you will discover that the most attractive option is to locate the facility in a friendlier regulatory environment. (Did you ever wonder why there is so much airplane painting going on in Roswell, NM?)
Jim Rennison