Other Air Forces in Indochina
Though the air war over Indochina may be largely thought of as being fought between the French Air Force and Aeronavale in the air and the Viet Minh on the ground, there were other major powers involved, to varying extents.
The RAF in Indochina, 1945-1946
With the end of the Second World War, it became necessary to send forces to Indochina to disarm the occupying Japanese troops and generally maintain order until the restoration of civilian government. The French armed forces were in no condition to immediately return to their former possession, and hence the forces of a foreign power were required. Following a long and bewildering series of manoeuvers, the British were given the mandate of occupying southern Indochina (below the 16th parallel) to disarm and concentrate the Japanese forces for eventual repatriation, liberate allied prisoners of war, and maintain law and order and internal security, until relieved by the post-war government of French Indochina. Under difficult circumstances, the British forces made efforts to restore law and order. This appeared to many as outright sympathy with French demands for a return to the status quo, and a harsh stance against emergent Vietnamese nationalism.
The British forces under General Gracey included a small air contingent. This was composed of squadrons transferred from Burma. On 11 September 1945, ten Spitfire Mk.VIIIs of 273 Squadron left Mingaladon, Burma for Tan Son Nhut, via Bangkok, arriving on 19 September. They were joined by 34 photo- reconnaisance Mosquitos of 684 Squadron starting on 12 October. In November 1945, the war-weary Spitfire Mk.VIIIs of 273 Squadron were replaced by bubble-topped Mk.XIVs (possibly FR.XIVes); however their deployment was short lived, as the squadron flew its last operational sortie on 8 January, and was disbanded on 31 January 1946. The first two of 684 Squadron's Mosquitos departed for Bangkok on 12 January. RAF operations ceased on February 15, with the disestablishment of RAF Headquarters French Indochina. General logistical support was provided by Dakotas of 345 Wing, and 62 Squadron in particular.
Exactly how the aircraft were employed during their deployment is not clear. The only combat operation of the Spitfires took place on 11 December 1945, when a strafing mission was flown in support of a surrounded French force near Ban Me Thuot. Aside from this, only daily tactical reconnaisance and leaflet dropping sorties were flown.
Mention must be made of the so-called Gremlin Task Force, a small group of Japanese crewed ex-Japanese aircraft that flew logistical support and reconnaisance for the British, to help alleviate the severe transport shortage. It's likely that the aircraft of Task Force Gremlin were subsequently transferred to the French (see the Japanese aircraft in French service page)
The final postscript on British involvement in Indochina came in September 1954, in the wake of the Geneva accords, when HMS Warrior assisted in the relocation of civilians from Tonkin (North Vietnam).
Photographs of the aircraft during their deployment to Indochina are scrarce. It appears that they wore the standard South East Asia colours of the day, with the two-tone blue roundels. The Mosquitos wore overall silver dope, while the Spitfires wore camouflage. The old Aircam profile (no. 24) on the Mosquito depicts a Burma-based PR.XVI in the overall silver scheme, with black bands on the tail surfaces. The Spitfire Special from Quarter Scale Modeller includes photos of a nice model of a Tan Son Nhut based FR.XIVe with standard white wing and tail bands. This same FR.XIVe is depicted in Aircam's Supermarine Spitfire Mk.XII-24, with both a photograph (also in Francillon's Vietnam: the War in the Air) and a colour profile painting of MS - F (RN218), in ocean grey and dark green over medium sea grey with white wing and tail bands and a white spinner. The photo shows the starboard camera port to be covered (the outline of the port is evident, and the covering is taut across the opening, and not even with the curved surface of the fuselage). The port side profile does not show the typical painted-out large fuselage roundel, however the photo shows traces of its presence, though it appears to have been painted over with the appropriate camouflage colours, rather than just dark green as used on some aircraft. As to the wing insignia, all I can give is an educated guess: I assume the large roundels would have also been painted over with the appropriate colours, with some slight variation in shade due to wear.
Modelling these aircraft would appear to be a relatively simple proposition. Hasegawa has an excellent Spitfire VIII in 1:72, while Fujimi produces the bubble-topped Mk.XIV. Kits of single-stage Merlin-engined Mosquitos abound, but for the two stage engines of the Mk.XVI, you'll need to do some cross kitting or use a conversion (such as Paragon's just released set for the Hasegawa B.IV). Markings are straightforward, requiring only the relevant roundels and code letters.
For my take on the Fujimi FR.14e, click here, or click on the thumbnails:
Here's a Hasegawa Beaufighter X, one of three used for various duties by 684 squadron: 
References on this subject are few and far between. The most comprehensive (and reliable) coverage of the topic that I've found is Peter M. Dunn's The First Vietnam War. George Rosie's The British in Viet-Nam: How the Twenty-Five-Year War Began is useful, though it seems to contain some factual errors. Unfortunately, neither provides any photos.
Some mention should also be made of British operations in Indochina prior to the end of the Second World War. British aircraft were heavily involved in special duties (SD) work, dropping supplies and agents behind Japanese lines, using B-24s modified with dropping slides, Halifaxes, Catalinas, C-47s and Lysanders. In addition to the inherent dangers of such work, the pilots were at risk of being shot down by American fighters if they strayed into American zones, with a number of aircraft being lost under questionable circumstances.
The USAF and USN in Indochina, 1953-1955
Despite initial reluctance to aid the French in reclaiming their former colony, the US soon came to become heavily involved in supporting the war. Although overt American participation would not occur until the early '60s, a significant role was played in the waning days of French Indochina.
Aside from overt support in the form of large quantities of arms and aircraft (Bearcats and Invaders, for example), and small quantities of aircraft maintenance technicians, the first major form of American involvement in combat operations was a (somewhat) covert one. Civil Air Transport (CAT), the Nationalist China-based airline formed by Gen. Claire Chenault provided a number of American pilots to fly C-119s in support of the French forces at Dien Bien Phu. Such pilots were of course civilians, with no ties to the US government (despite the connections between the CIA and CAT).
Subsequently, the USAF became involved in providing transport for French soldiers from France to Indochina. France's limited air transport assets were stretched to the limit in Indochina, and the large numbers of new troops required to bolster the flagging effort on the ground simply could not be quickly transferred to the theatre. The answer came in the form of American C-124 Globemaster IIs, flying the long haul from France. Flights in support of the French continued until 1955.
Dien Bien Phu nearly provided the spark for initiating full American involvement in the war. Numerous planning sessions were held in Washington for a possible airstrike on the Viet Minh positions in the hills surrounding DBP, or the lines of support beyond the valley. Options went as far as a possible atomic bomb strike on the Viet Minh command, and possible into China. A massive conventional strike using B-29s of BombCom, the Pacific based Bomber Command, incorporating elements of the 19th, 98th and 307th BW and the 91st SRS was seriously considered. Cover for the strike was to have been provided by Navy jets flying of carriers in the Gulf of Tonkin. Such cover was necessary in light of the possibility of intervention by Chinese MiGs. Eventually these plans, known collectively as operation Vulture (Vautour) came to nothing, as the US demanded international cooperation as a condition of its involvement, and the British in particular felt that such a strike would have little effect on the final outcome of the war. It appears that rumours of B-29s with French roundels in the Pacific bases are unfounded.
Although the airstrike never came to fruition, USN aircraft did fly reconnaissance missions in support of the possible strike, and forces on the ground at DBP reported sighting jet contrails high in the sky. From March to April 1954, the USS Essex and Wasp flew numerous sorties in the Gulf of Tonkin. In May, the USS Phillipine Sea took up position in what was to later become Yankee Station, while the USS Boxer took part in operations from March to June 1954.
The operations of CAT are well detailed in William Leary's Perilous Missions. Christopher Robbins' Air America also provides a chapter on CAT operations, though with nowhere near the thoroughness of Leary. The best reference on Operation Vulture that I have found is John Prados' The Sky Would Fall. Bernard Fall's Hell in a Very Small Place provides insight into the view from the French side.