I have extensive experience with the fuji and kodak products myself and I have found them both to be very good films. Fuji Velvia 50 is highly saturated super fine grained film and is used to its fullest potential with fast pro lenses with tack-sharp optics. The same goes for kodak 100vs and you can still get premium results with lesser quality lenses. I think that in a 100 speed E6 film E100s is actually the best choice for aviation photography because it is less saturated and gives very sharp true-to-life colors. But for the ultimate in sharpness, true color representation, and archival keeping, the best choice are Kodak Kodachrome films. The 25 and 64 speed films are both super sharp and give the best color representation that I have seen. I have switched over all of my photography work to these films in the past year and have also been using Kodachrome 200, which can be pushed to ISO 800 if necessary. Now I know a lot of folks will object to Kodachrome on the grounds of availability of processing, and price, but K-14 prosessing is easily obtained with prepaid processing mailers. I understand the objections but the best and longest lasting images come from Kodachrome in mine and many others opinions, so if you are inclined to get the most out of your photography I think K14 is the best way to go.
If you know what's really going on then you'll know what to do