Geographically, Cambodia is nowhere close to Indonesia major cities, and economic/tourism activities between both countries had been quite low. However, Indonesia is undoubtledly significant friend of Cambodia, Indonesia was the most influental player in bring peace to Cambodia following the fall of brual Khmer Rouge regime. Indonesia also deployed thousands peacekeeper army to Cambodian jungles to protect the civilians from sporadic attack by remaining Khmer Rouge fighters. Until this moment, the older generation know Indonesia as their "protector". Until now, Indonesian elite forces send its best trainer to Cambodia to train Cambodian para-commando, and PM's elite guards.
I once took a walk in suburban areas outside Phnom Penh and found a very heartwarming scene, where some houses hang Indonesian president photos.
Trade between two countries remain low at $270 million at its peak in 2007 (source) with Indonesia enjoyed the trade surplus. Cambodian tourists visiting Indonesia are still low compared to neighbors like Singapore, or Malaysia. However, considering the potentials that trade between two countries are always on uptrends, and Indonesian tourist visiting Cambodia increases significantly these years, there's really a need for linking Indonesian-Cambodia by air.
Indonesian giant group, PT RAJAWALI,once planned to setup Cambodian-based airline and open direct flight Jakarta-Phnom Penh, however plan was turned down due to some complex procedures in Cambodia. The plan of connecting two nations is still up in the air when PM Hun Sen urged to soon open the direct flight beetween Cambodia-Indonesia at all cost, esp to tap potentials Indonesia has. He said that both countries are host to two world's largest historical monuments...Angkor Wat, and Borobudur.
I spent 9 months in Cambodia last year, and i could see that many Indonesian products are now available at stores nationwide. I also met huge number of Indonesians visiting Cambodia for biz and vacation.
Indonesia now really needs to expand its economic influence to a broader lines, and Indochina region (Laos, Vietnam, Cambodia) really has so much to offer and tap.