"Pilots, Man Your Planes!"   
                                         WWII U.S. Naval Aviation Collector's Guide                                                                              
The 'Chute Shop
First published in National Geographic Magazine's August 1945 issue, in a sixteen page color supplement titled "Take-off for Japan", this photo's subject is the Vanderwall twins, Andrew (at left) and Arnold. Both were aviation ordnancemen 1st class and served as turret gunners with VT-7. They are seen here aboard USS Hancock on February 19, 1945. Many features of their attire and equipment are notable, not the least of which are their large rayon identification flags, which appear to be cut down from MIS-X type 4 Blood Chits (see Baldwin & McGarry's LAST HOPE, page 109) and CBI shoulder patches. Our focus, however, is on the blue canvas, rigger made, knife pockets on their right legs.
As previously noted, the typical Navy pilot or aircrewman was burdened with a myriad of survival equipment, the majority of which was carried on the upper body. It became common place to try and distribute the load more evenly as to make the time they spent in the cockpit, cabin, or turret a bit more comfortable. One practical and popular solution was the addition of type-specific pockets that were sewn directly to the legs of the flight suit to stow some of their gear. Most common was a pocket to accomodate the survival knife in it's sheath. As always, the parachute riggers tasked with this job used the materials that were best suited. In this case, either the gray cotton processed fabric used to make parachute packs or the heavier blue waterproof canvas used for cockpit and engine covers.

Below:  From the collection of Jerry K., we have a beautiful example of the latter material in use on this lightweight tropical nylon flight suit as used by a Marine Corps lieutenant. With it's upper right thigh location, the Mk-I knife would have been instantly available to deflate an inadvertently inflated pararaft (which could prove deadly in a cramped cockpit) or break through a plexiglass canopy if conventional egress was otherwise prevented.

Below:  Made of similar material, this pocket, for a large MK-II knife, is sewn on a wartime contract Z-2 anti-G suit. The keeper strap is made from black goggle strap elastic and secured with a Carr snap.
Above:  A well known photo. Note the cockpit covers, of blue waterproof canvas, on the two Hellcats.

Below:  Ken Walsh, USMC ace and MOH recipient, standing by a Corsair fitted with blue waterproof canvas engine and propeller hub covers.
Above:  Not a knife pocket, but another example of a rigger's use of the blue canvas, employed here as a waterproof cover for a QAS parachute seat cushion.

Below:  Found on the lower left leg of an M-668 summer flight suit, we have an example made from parachute pack fabric. The upper part of the Western shark knife's leather scabbard is also secured with a Carr snap.
Below:  Also from the collection of Jerry K., this is a very simple, but effective, pocket for a Mk-I knife and scabbard, made from gray fabric with the rough side out and no edge tape, applied to an M-668 suit.
Above:  A small pocket, similar in size to the one just shown, appears in this photo of VT-2 aircrewmen preparing for a mission, however, a light color edge tape has been used, giving it a more finished appearance.

Below:  No telling who made our final example, but it may have been a rigger, a metalsmith, a cobbler, or the airman himself. This sturdy rig is nicely named to Leland Leroy Wainscott, of the "U.S. Navy Air Corps", a designation you don't run across every day. Preliminary research indicates he was an Aviation Ordnanceman, so possibly a TBF/TBM turret gunner.
Above: A VT-2 crew from U.S.S. Hornet go over the flight plan before a strike mission. The pilot has a large flapped knife pocket.

Below: VC-21 FM-2 Wildcat pilots, LT (jg) C.R. Bradford, at left with a small knife pocket, and his wingman, ENS W.N. Penny, prepair for their next flight from CVE-77 during a period of intense Japanese air attacks. The pair repulsed one six plane formation, shooting down three and scattering the others.
We don't want to give the wrong impression that these knife pockets will only be found on very late-war cotton or nylon flight suits. Below is an earlier vintage M-426a summer suit from the collection of Andy at The Old Footlocker Military Surplus. http://www.pensmilsurp.com/
He says:
"Here are a few shots of the knife on the flight suit that I found in Pensacola a few years back. It came with a rather large group of stuff. This officer served from 1936-60 and during the war, he flew the OSU-2 in the Pacific, was a flight instructor in Pensacola, and later commanded the Jolly Rogers in 1946."
Thanks Andy!

At bottom, VF-6's Roland Baker can be seen wearing the mid-war style AN-S-31 suit, with added knife pocket, in March of 1945.