I managed to find some links for you:
http://marshall.csu.edu.au/html/WWII/SeaPlaneOps.html
Long-range seaplanes became available in 1936 with the introduction of the Kawanishi H6K flying boat and in 1942 with the introduction of the Kawanishi H8K flying boat. In addition, single engine float planes were used for anti-submarine patrol. The seaplane base in Jaluit, for example, is known to have harbored in mid-1943 the Mitsubishi A6M2-N's ("Rufe"), a float plane version of the "zero" fighter The aircraft visible on a contemporary photograph possibly represent two air wings and all belong to the 802nd Kokutai (Squadron).
The bulk of the military operations of the sea planes constituted the flying of long search patrols in a set search triangle, looking for enemy submarines and surface shipping. The planes were equipped with communications and small anti-submarine bombs. Attack operations were less common:
The Japanese attack on Pearl Harbor on December 8th, 1941, was partially launched from bases in the Marshall Islands. Not only came the submarines providing the submarine screen from the base of the 6th submarine fleet in Kwajalein, but also several flying boats taking part in the Pearl Harbor as well as in the raids on the U.S. bases on Wake I., Howland I. and Canton I. were launched from the seaplane bases of the Yokohama Kokutai (later 802nd Kokutai) on Wotje and Jaluit.
Kawanishi flying boats based at Jaluit and Wotje were also used as long-range bombers and on March 4-5, 1942, bombed Oahu, Hawaii, in retaliation of the U.S. carrier strike against the Marshalls in early February 1943. The French Frigate Shoals, some 700 miles northwest of Hawaii Island, were to be used by the Japanese seaplanes as a rendezvous point with submarines carrying fuel and bombs. The French Frigate Shoals had not been used by the Japanese Fleet as a seaplane base in the 1941 carrier attack on Pearl Harbor which began the Pacific War. Having come into classified U.S.Navy Information with the fall of Wake I. on 23 December 1941, however, the Japanese then possibly decided to utilize the atoll. Refueling and arming of two Kawanishi H8K flying boats took place in the night of 3 March 1942 (U.S. time), which carried out a successful raid on Pearl Harbor the day after.
Another scheduled Japanese rendezvous of three submarines with long-range flying-boats and submarines at French Frigate Shoals had to be called off between May 26th to 31st. The flying-boats were to have reconnoitered Pearl Harbor in preparation for the attack on Midway. Following the Battle of Midway, the U.S. Navy erected a complete Naval Air Station on French Frigate Shoals, which precluded any further Japanese rendezvous.
In September 1942 another major flying boat raid was conducted, attacking the U.S. bases on Funafuti, Tuvalu, and Canton I. It appears that these flying boats either never returned to their home bases in the Marshall Islands or that they were relocated in order to avoid any psychological draw-backs for the 802ND. In addition, flying boats from the Marshall Islands were once more scheduled to bomb Pearl Harbor . As had been the case in March 1942, the French Frigate Shoals were to be used by the Japanese seaplanes as a rendezvous point with a submarine carrying fuel and bombs. However, the Pearl Harbor raid did not eventuate, as the submarine scheduled for a rendezvous with the flying boats found the shoals occupied by a U.S. Naval Air Unit and the rendezvous had to be called off.
As the war progressed, and the U.S. air attacks against the Marshalls become more common, flying boat operations became less frequent, and a number of boats were sunk at their moorings by U.S. fire, such as the three flying boats of Ebeye or the boat off Wotje.
The last Japanese flying boat operations in the Marshall islands occurred in the first and second week of February 1944, when flying boats from the Japanese headquarters in Chuuk flew to the then by-passed bases of Taroa/Maloelap, Wotje and Mile to take off fighter and bomber pilots stranded there.
The above was just a excerpt you should also check out:
http://www.stelzriede.com/ms/html/mshwfug1.htm
I don't think the Japaneese ever had plans for the Panama Canal, but the Germans had a plan in which they were to disassemble Stukas, ship them to S. America in U-Boats, and launch from makeshift airfields.
Hope this helps [img]smile.gif[/img]
