Headsethair,
Diesel fuel isn't used in the new aviation diesels, they were designed for Jet A-1 as mentioned earlier. This allows the aircraft to be refuelled at most airports, using fuel that meets aviation quality standards (water checks etc).
However, if the Jet fuel does need pre-heating, that feature can be designed in. Some helicopters, for example the S-76, have engine oil heated fuel components (such as filters) where the waxing problem might occur. Most modern diesel cars also have electric fuel pre-heaters.
Or you could try the old lorry driver's trick of lighting a fire under the engine on cold mornings.........
Hehe