Putting together a versatile travel wardrobe

Come spring, that young man's fancy may lightly turn toward thoughts of love, but the object of his affections is more likely preoccupied with planning her new wardrobe - the additions to be made, the subtractions, and serious reflections about holidays and travel.

Separates and coordinates are probably the most overworked words in today's fashion vocabulary. Yet if anything is really going to work in a capsule wardrobe, these are the basic concepts.

There's a lesson to learn from all the interchangeable separates that constitute flight hostesses' wardrobes on most major airlines. These are no longer the strictly tailored dark suits worn with a mannish white shirt and necktie and the unbecoming cap of yesteryear, but pretty, feminine clothes that every woman would enjoy wearing in private life. The keynote is uniformity, rather than the impersonal connotation of a uniform, with all the pieces going together and switching around to double or triple the scope.

With jet travel, one may take off from northern climes in a blizzard and end up several hours later in the tropics, so layering also proves a very effective solution.

Carven, whose famous green and white striped decor and dress boxes epitomize the couture house that dates back to the late 1930s, has designed the official wardrobes for both the Parisian meter maids and the new ensembles for the hostesses on Air Inter, the domestic French airline. Those dazzling damsels who smack parking tickets on any car that is a fraction of a minute overdue and are the terror of every driver in Paris, used to be called ''Les aubergines'' (eggplants) because of the somber color of their old uniforms.

Then, three years ago, along came Carven to change all that. ''Les girls'' are now resplendent in bright blue, a color far easier for any nervous driver to spot as they march ominously down the street issuing tickets right and left. Now they have been dubbed ''Les Pervanches,'' meaning periwinkle posies, though the term is misleading as the color is really a vivid cornflower hue rather than blue with a lavender cast.

The government-issued wardrobe provides for chilly winter weather as well as spring and summer. It includes a warm overcoat, a suit with both trousers and a slim skirt, a striped blouse, and a matching dress, accessorized with a becoming hat and printed scarf.

Following the success of the ''Pervanche'' outfits, Carven was asked to create wardrobes for the high-flying Air Inter hostesses. This complete wardrobe would see any traveler round the world through every climate, with the underlying theme of switchmates based on a navy blue and beige color scheme. Every piece - including two woolen suits, two pairs of trousers, a topcoat, a striped silk dress and blouse in the matching print, the knit cardigan, pullover , and sleeveless sweater - goes with everything else, adding up to almost unlimited combinations.

Choosing from all these harmonious components, each hostess dresses to please herself. Depending on the length of her trip and destination, she totes a few extra pieces in a small carry-on bag. Unlike several other airlines where every hostess is dressed identically, the Air Inter wardrobes are infinitely varied and as pleasing for the passengers as for the women themselves.

What salient schemes to adapt in our own wardrobes! The keynote is two or three basic colors and the will power never to deviate from a carefully established travel plan. Resist the impulse to buy that poison green blouse just because it momentarily seems pretty and is on sale but clashes with everything else you are popping in your suitcase.

So bon voyage. Edit carefully, travel lightly, and remember that a porter is hard to find these days.