He was brought up in Nanaimo, though some of his schooling took place in Victoria, British Columbia and Oakland, California, due to his father's occasional pursuit of gold mining.

"[6] Collishaw's first encounter with a German aircraft was while flying escort duty on 3 Wing's first large-scale raid into Germany, against the Mauser Rifle Factory at Oberndorf, on 12 October 1916.

[7] Collishaw's first confirmed victories occurred on 2 October, while he was ferrying a new Strutter from Wing Headquarters (at Luxeuil) to his squadron's new forward base (at Ochey, France) alone (without an observer).

Finally, after what seemed an eternity, there was no more gunfire and I realized that the remaining scouts had left, possibly because they were running low on fuel...[8]Collishaw then attempted to return to allied lines, but had become disoriented.

On 23 January 1917, returning from a wing raid at the blast furnaces at Burbach, he had a "particularly desperate" encounter with a Fokker D.III, and he was forced down on the allied side near Nancy.

3 Naval Squadron, which had just been established at the beginning of the month and was operating in direct support of the army and RFC at Vert Galand near Somme plain,[12] and equipped with the then-somewhat-dated Sopwith Pups.

[13] One thing Collishaw noticed was that the pace of missions had steeply increased: instead of flying raids every week or two, as had been done at 3 Wing, at Naval 3, pilots could expect one or more patrols every day, and rarely without some sort of enemy encounter.

Still, he added two to his tally before suffering another incident where, in combat at high altitude, bullets once again hit his goggles, and in response he threw off his entire face-mask, causing his face to become badly swollen by frostbite.

Naval 10 was slowly being equipped with the new, fast-climbing and maneuverable Sopwith Triplane, and Collishaw found the aircraft "delightful",[16] though still wished for a second forward-firing Vickers machine gun.

)[17] He had his first combat in a Triplane on 28 April, firing on a two-seater in the morning (but foiled by a gun jam), and then later in the day attacking four German fighters (while covering a disabled seaplane off Nieuport) and possibly surprising them with its performance.

Gerry Nash was the first to score a victory, on 21 May, after diving on a flight of five German scouts, and leaving the pilot of his target slumping back in his cockpit, entering a side-slipping spin.

5 June started with a long-range high-altitude offensive patrol over Menin; Collishaw leading a whole-formation firing charge against a two-seater, which went down in flames.

... After the war's end, however, I learned from German sources the details of Allmenroeder's [sic] death – how he was hit by a burst of fire from extreme range and went down to crash between the lines in the Ypres area.

[39] The second was when shrapnel from anti-aircraft fire sent two sizable pieces of his engine cowling flying, one catching in the wing wires, drastically changing the drag profile of the plane and throwing it into a dangerous spin.

Collishaw later learned that all the squadron's guns were jammed and, years after the war, he met with the German flight leader from that day, who explained that they had experienced the exact same thing.

He was informed by the Air Ministry that he might participate in an attempt to fly across the Atlantic using a 'Super' Handley Page V/1500 long-range bomber, but this was scrapped due to unwanted media publicity.

The British government decided that in addition to the current Military Mission that acted in support of General Anton Denikin's White Russian forces, a squadron would be sent to operate under him, and Collishaw was chosen to be in command.

[55] Given most of the ground fighting in the region was being conducted by horseback cavalry units, the squadron was tooled and designed to operate out of special rail trains – one for each flight (there eventually would be four) – which would be able to quickly follow the front lines, jumping from one suitable makeshift aerodrome or landing site to another.

Collishaw and his pilots were adept at using their advantages and equipment to maximum effect – reconnaissance, bombing, and strafing inflicted thousands of casualties (particularly after receiving a detachment of Sopwith Camels)[57] on the Red Army and assisted greatly in the initial advances of the White Russian forces through the summer and fall.

Their operations were conducted with relative impunity – though small-arms fire would at times get intense, and some fortifications and ships housed dangerous arrays of anti-aircraft batteries.

The squadron met with virtually no airborne resistance throughout the campaign, only on a few occasions shooting down some Nieuport and Albatros aircraft (displaying various markings – some having black crosses[58]) that attacked.

[59] In early-mid October, just as White Russian forces secured their widest gains to-date, Collishaw came down with Typhus Fever, which was wildly endemic in the region.

It also meant going without supplies such as munitions, food, coal, and water for the locomotives, all of which had to be foraged at regular stops along the rail line by available troops in the combined army trains.

Collishaw's closest call during this campaign, besides the chase by rail and his fight with typhus, was while leading a late-February bombing raid in a DH.9 – his engine was hit by gunfire from the ground, causing it to lose most of its horsepower.

Forced to land, he was incredibly fortunate that his engine remained functional (though reduced) and recent weather had combined (being very cold and windy, filling in any dips or trenches in the landscape) to make possible the subsequent twenty miles of taxiing he completed in his aircraft to friendly territory.

This was a tough challenge considering that he was greatly outnumbered (150 aircraft vs. the Italians' nearly 400), and his men were flying outdated Gloster Gladiator biplane fighters and Vickers Wellesley bombers.

However these transfers were paid back in December by fortunate shipments (transport convoys had to run a very dangerous gauntlet through the Mediterranean) of Hurricanes and Wellington bombers – several squadrons worth.

Promoted to his final rank of Air Vice Marshal, he was given a headquarters posting in Fighter Command in Scapa Flow, Scotland, and remained there until July 1943, when he "was retired".

Yet if I am known at all to my fellow Canadians and others it is through more carefree days, when as a young fighter pilot, with the limited responsibilities of a flight and squadron commander on the Western Front, I had the good fortune to shoot down a number of the enemy without in turn being killed.

[87][88] As with some other distinguished First World War flight and squadron leaders, Collishaw was supposedly noted as occasionally helping bolster the confidence of new pilots by attributing victories or successful combat actions to them.