または「次便発送サービス」

通例"next flight out service"とは「急ぎの荷物は次の便で直ちに発送しますよ」というサービス。

If you haven't had to move shipments by air on a short term or emergency basis with your Boston courier service, then you may be unsure of what a courier means when they advertise that they offer NFO service. NFO stands for next flight out, and when a courier offers this service, it means that if you need to get something to the other side of the country as fast as humanely possible, then they will arrange to have the package on the next plane that is leaving the airport headed towards your destination. This is often the fastest way to get any kind of package from point A to point B, which is why many people look for it in their delivery company, and why many of those companies who do offer the service should be sure to mention it in their advertising or on their website.
http://www.articlesnatch.com/Article/Definition-of-NFO-Couri...