There is insufficient research into the development of appropriate types of vessel and aircraft for inter-island and feeder transport services: the transport development costs may be beyond the means of many island communities, but so may be the fixed infrastructure the transport services require. These internal transportation problems are aggravated by the fact that external transport services available to island countries continue to deteriorate, since technical progress in aviation and shipping is biased against small communities where the unit costs of operations tend to be correspondingly higher. Inadequate internal and external transport services are obstacles to island development, affecting tourism, conversion and production, exports, international political and diplomatic action, and scientific, technical and cultural interchange.