My answer has wandered so far from the question that I've changed the subject line.
There's no way a skirt is going to be modest on a recumbent
-- whatever you wear underneath is going to become drawers in that position.
One solution is to attach the skirt when you get off -- button-onto-the-waistband panels, or a wrap skirt. I tried a wrap skirt once, when I went to a meeting on a bike. The next time I had a meeting, though, I packed full regalia in my panniers and changed in a handicap stall before going to the meeting. I wish the salwar kameez had been in style then -- putting on panty hose standing up is not fun.) (Nowadays I'll wear my black polywool slacks under *any* dress on winter days.)
In the days when I went places other than the grocery store, I spent a lot of time regretting that "fluff crepe" was a flash in the pan. I made a dress from this in the sixties
-- and carried the entire project to and from work[1] in a mushroom bag half the size of a lunch bag. Fluff Crepe was neither fluffy nor crepe -- it was a very thin, but opaque, plain-woven polyester that had a finish similar to plisse'
-- but the scale was much wider, and there was hardly any difference between the hills and the hollows. The result was a dress that looked like any dressy print, but you couldn't wrinkle it if you tried. And it took almost no room in a suitcase!
With age and increasing fluffiness, I'm coming more and more to prefer dresses and long shirts to separate skirts -- I still love my pleated broadfall skirt for the huge pockets, but when I wore it (for the first time this year) last Sunday, I wore a hip-length matching jacket. And the beta for my new shirts comes to mid-thigh, with plans to make the real ones kameez-length. Or at least down to the knee.
(Which reminds me: I'd better get on with sewing snaps on it so I can wear it around the house and get an idea of whether I want to change the pattern before cutting my lovely border print. 50/50 linen/cotton, as soft as chickenfeed sacks, closer woven, and I got the very last bit of it -- Phoenix had to give me the ends of two different rolls to make up my ten yards.)
When I was on the 5-Boro Bike Tour many years ago (I don't recall the year, but it was the year they motor-paced the leaders to a *maximum* speed of 6 mph, so I walked a substantial fraction of the way.), I saw a woman in a floor-sweeping dress walking around one of the rest stops. Later I saw her riding in slacks, with a great poof of fabric around her waist. Never got close enough to ask her how she managed that. It would be useless on a recumbent anyhow, since you'd have to sit on the pouf.
(If you *must* pace a bike tour at walking speed, you could at least *tell* the participants that you are doing it. Every last one of the thousands of riders thought that he had the bad luck to be trapped behind a knot of incredibly-slow riders, and if he could only bull his way through it, he'd come to the open space in front of them and be able to balance. This made the ride *extremely* unpleasant. And if I'd known ahead of time that it was a walking tour, I'd have worn walking shoes.)
I greatly prefer long shirts to skirts sewn to pants. (On the other hand, a lots-of-strips skirt that doesn't drop with your pants can be a bit hard to keep sanitary at pit stops.) A long shirt over a separate skirt can be made with no waistline, which is flattering to those of us who are a bit fluffier than we used to be. Also, a given skirt length is more modest when thought of as a long shirt, rather than as a short skirt.
My summer costume riding costume is black linen slacks, cut four inches longer than knee length, with elastic in the hems cut to fit around the notch below the knee. The poofy knicker-knee looks odd, but gives me plenty of freedom of movement.
In the winter, it's wool tights -- if I ever get around to patching them. (I found my wool sewing thread yesterday. My supply of patching cloth is rather pitiful, though. )
Spring and fall, I wear my regular slacks with a pants protector on one leg, and a tape tied below the knee (again producing a knicker effect for freedom to bend said knee) on the other, with a safety pin or two to keep the hem out of the chain.
Not getting caught in the chain -- and not showing anything when I step over the top bar -- trumps everything else in cycling-costume design. With not getting run over running a close second; I don't look good in International Orange, so I wear safety-yellow shirts. Besides, yellow is better than orange when the seeing is bad, and in bright sunshine, when I.O. is slightly better, being visible is comparatively easy.
My only concession to appearance is to make everything that is likely to end up black, black to start with. I once saw a man who had been riding a bike in yellow rain pants, and I'd take *risks* to avoid looking like *that*. A yellow jacket or jersey is sufficient to let drivers know I'm on the road -- the legs don't show much anyway.
The dime dropped a few years ago, and both my new jerseys are T-shirts with added pockets. Fit better, look better, easier to make than plackets -- and when I want to put on a jersey without taking my helmet off, I put in a *separating* zipper that goes the full length of the front. As for opening the placket for ventilation -- if I don't have all that placket-support stuff in there, I don't *need* to.
The linen jersey, of course, has a placket, since I didn't want a neck large enough to pass over my head.
Joy Beeson