((Maybe it's more my perspective >_< I'm thinking about vehicles and other utility skills. Alice's Planes could apply to Cars and other vehicles at +1 maybe, only if she has +3 in that skill? I'm inexperienced. What was going in my mind was the cross-overs for categories grouped in the spoiler; those grouped skills, at +3, give other skills in the same batch, a +1.))
Explosive: Used for rocket launchers, grenades, and other fired or thrown explosives.
Demolitions: Used for planted explosives or landmines.
First Aid: Basic medical skills. Usually requires minimal supplies, but also has limited effect.
Medical Training: Like first aid but needs special gear and has a greater effect.
Car: Used to drive cars, trucks and civilian vehicles
Tank: Used to drive tanks and armored ground vehicles
Plane: Used to fly planes, gliders, autogyros, etc.
Boat: Used for controlling ships, boats and submarines.
Operator: Used to operate machinery, such as Radios, Trains, tractors, and cranes.
Mechanic: Used to repair machinery and vehicles. Usually requires parts.
Traps: Used for making, and avoiding, traps.
Camouflage: Use of various items and techniques to hide yourself or someone/something else. {Probably crosses with a statistic, like Senses. I'm unsure where Senses was even used at all, unless it's for hidden rolls}
Interrogation: Used to get info out of an enemy
Language: Used to speak to others in other languages.
((I get what you're trying to do here, but I don't think it's a good solution. Most plainly, having a +1 in anything is near meaningless; it upgrades successes (4s) to crits (5s). Most of the time those don't have any practical difference.
Perhaps it could be significant if the +1 was in addition to base skill, so +3 in plane with +2 in car and tank means you effectively have +3 in all three skills... but this still doesn't solve the actual issue of specialists having nothing to do when their specialties aren't required, because then that person can't do anything reliably except drive.
A decent solution would be to generalize skills like Plane, making it "driver" or something that affects all vehicles, so that vehicle operators are always useful as long as there's a vehicle (which is still rarer than "scoped rifles" or "camoflage" being useful). Other skill groups that might be good to fuse are Languages/Interrogation, and Operator/Mechanic/~maybetraps.
Camoflage also isn't versatile enough, you should be able to roll it for all other skills with a slight penalty. You're tricking the universe into believing you're good at the thing.
...Anyway, this is forgetting that +0 is still RTD, which has ~50% success rate. Even if you have no skills whatsoever, you can still be useful if you're just cautious.))
I feel like that solution would be overcombining and oversimplification, leading to having one or two skillsets be frustratingly overpowered as in DIG (and, of course, ER and OL).
That said, I agree that many specialized skills, especially such as planes, boat, and interrogation, are quite limited in terms of actual gameplay value, mostly due ot the setting. But all those skills
are specializations, and people train heavily in such things before using them in the real world, to the expense of other skills (with the exception of automotives, unless we are talking racers or offroading).
Plane skill is mostly useful either in single player mode, or with a group of other player pilots, or flying the flying fortresses as in that test game we did on r20 last year. Perhaps that was what PW had in mind with the two flying options for this mission?
I think a possible solution would simply be to label certain skills in a separate group as "specializations." You take a spec at the expense of two standard skills, and accept that this character has a niche role - it's what I did with mechanic. (or, conversely, each character gets one "spec" slot for one of those skills, so everyone has a single situational strength, which useless in most other contexts.)
maybe eliminate the operator and automobile skills and allow players with those skills to move their points, if it's that big an issue, but I don't think merging mechanic and traps skill is wise, really, nor adding explosives to that grouping. I've gotten a lot of use out of traps skill and explosives skill, for instance, so each of those skills is of value in it's own right -though hopefully neither are of use on this mission
(actually, traps probably will be, since we are dealing with spies who probably have tripwires and other alarm mechanisms, at the very least).