"Neatness," so it is said, "is a Danish virtue," nowhere practiced so assiduously, perhaps, as on the tiny Baltic Sea island of Aero, an out-of-the-way escape of pastoral villages, flower-filled hillsides and gorgeous seascapes from practically any vantage.

It's not a regimented "neatness," certainly, since the Danes are a rather free-spirited people, but a proper well-scrubbed tidiness that bespeaks both industry and pride. It appeals to the traveler in the same way as does a comfortable, well-maintained hotel at the end of a long trip.

Only 22 miles long and six miles wide (at its widest point), the island -- home of one of Europe's major ports a century ago -- is a delight from one end to the other. It is not a place that you hurry to, however, for a quick day of sightseeing. You go to relax and to linger -- a quiet country interlude, say, in a busy holiday of city tours.

Tidy, yes, and cozy, charming and quaint: The very qualities that draw transatlantic travelers into the European countryside flourish on Aero. In a sense it is a microcosm of Denmark, one that incorporates its most-pleasing aspects -- a blend of the land and the sea and a bit of fantasy, too.

Here you find winding, one-lane roads that wander past green pastures or along the coastline; small, sandy or pebble beaches that draw sunbathers (sometimes nude) and swimmers to the Baltic's chilly waters; rolling fields ripe with summer's yield; thatched-roof farmhouses with bunches of hollyhocks growing at the doorstep; steepled churches from the island's ancient past; and a scattering of country and seaside villages, each individual, but usually possessing at least one small hotel or inn and a bakery selling some of Europe's sweetest pastries.

And, to complete this pleasant scene, there is the colorful market town of Aeroskobing, Denmark's most carefully preserved medieval village, dating from the 13th century. Lining its narrow cobblestone streets are rows of tiny, gingerbread houses, uniformly roofed with rounded tiles and painted in blues and reds and golds and other vibrant hues. Once they were the homes of Aero's seafaring captains.

Many of these houses -- the oldest was built in 1642 -- feature distinctive doors that really are intricate, hand-carved works of art; and hanging alongside the entrance ways are elaborate cast-iron lamps that cast a cheery light at nightfall.

A workman pedals by, the day's fresh bread strapped to the rear fender of his bicycle. The town mailman props his bicycle under the shade of a large tree while he makes a delivery. A housewife polishes once again windows that already gleam. The aroma from the bakery, identified by the emblem of a golden pastry displayed high above the door, tempts and then captures a pair of hungry customers.

No wonder, then, that after a day or two on Aero you are convinced you have stepped into the fairy-tale world of author Hans Christian Andersen, who was, in fact, born not far away in Odense, on the neighboring island of Fyn. Swans glide in the bay outside Aeroskobing -- surely, you think, descendants of The Ugly Duckling.

Aero is about a five-hour trip from Copenhagen, first by train or rented car and then a 75-minute ride on the auto-ferry from Svendborg to Aeroskobing. It is located southwest of the capital, one of the many Danish islands in the archipelago north of the German coast.

Fans of Andersen can stop en route in Odense to tour the little half-timbered house where he was born in 1805 and which is now an Andersen museum. Beyond, in Aero, they will find a small bit of rural Denmark little changed from Andersen's day.

It is appropriate that visitors arrive on Aero by sea, because a good part of its livelihood remains linked to the sea. Marstal, the island's largest town (there are no cities since Aero's entire population is only about 8,500) was home at the turn of the century to more than 100 ocean-going schooners, many of them transporting codfish from Newfoundland in Canada to Spain and Portugal.

Today Marstal remains home port for a modern fleet of coastal steamers, its harbor busy with both commercial and pleasure craft. Two Marstal shipyards continue to turn out large fishing trawlers.

Across the island, on its northwestern tip, tiny Soby is a quiet fishing village, its harbor filled, too, with the vessels of its trade. And elsewhere there are frequent reminders of Aero's seafaring heritage, not the least of which is the amazing Bottle Ship Collection in Aeroskobing. These miniature ships within a bottle -- more than 500 of them -- were carved on the island decades ago by a retired ship's cook known as "Bottle Peter."

Similarly important to Aero's economy is agriculture, and so the island's interior is a patchwork quilt of fields and lush green pastures spread across a slightly rolling terrain. There are hills on Aero, usually topped by a village church, but the inclines are gentle.

Many of the farmhouses, as colorfully painted as the homes in town, are connected to the barn and other outbuildings, often forming a U-shaped structure around a cobblestone courtyard. With fat cows grazing in the fields behind and tulips and hollyhocks blooming in the garden, the farmyard scene is right out of a child's storybook.

We went to Aero for an early summer bicycling holiday, pedaling country and coastal back roads from one small inn to the next for seven days and staying in a different inn each night. American tourists have just begun to discover the island, though it has long been popular with vacationing Danes.

Our trip was a few years back, memories of it refreshened now by Denmark's celebration this year of the 150th anniversary of Andersen's first book of fairy tales. Current reports from Aero assure, however, that it remains unchanged, still the charming place we recall.

As cycling excursions go, our itinerary -- encircling the island -- was something of a joke. Even at a relaxed pace, the next village was never more than a couple of hours away. We probably could have traced the entire route around Aero in one long, fast day.

We adjusted rather quickly though. We dallied at breakfast, an outdoor feast of new-baked bread and rolls with butter and jam; slices of ham and strong white cheese; and milk and tea or coffee.

We lingered again at lunch, usually a sampling of Denmark's open-faced sandwiches called smorrebrod (pickled herring and onions; ham, cheese and salami; roast beef and fresh horseradish; and lots of butter), all washed down with good Danish beer.

And, to be honest, we rarely passed a bakery without indulging in just one more pastry.

Once or twice we cycled quickly to our next destination, and then left our bikes for long rambles through the surrounding countryside or along the beach. A couple of times we sprawled out on a high bluff and spent an hour or two reading and sunning. The hardy on the beach swam, but it was considered sufficiently brave to wade up to your knees in the chilly waters.

We strolled again in the long after-dinner twilight of the north, and capped each night with a visit to the village tavern for a sip of Cherry Heering, the famous Danish cherry liqueur.

Similar self-guided tours, available through the Aeroskobing tourism office, are about $185 per person, including seven nights at inns in rooms with shared bath, breakfast and dinner daily and bicycle rental. Booking independently, a room for two at an inn (with shared bath) is about $26 a night.

Travelers who don't want to cycle or hike can get about the island on the frequent and excellent local bus service between the villages. Many islanders, particularly the younger ones, speak at least some English.

Though Aero offers little more in the way of sightseeing attractions or activities beyond those I have described, they were not missed. Instead, there are simply the island's picture-perfect country views and seascapes, to be enjoyed leisurely a few miles at a time.

All of it neatly spic-and-span, of course, the way a storybook island ought to be.

For more information about Aero, accommodations and cycling tours, contact: Danish Tourist Board, 655 Third Ave., New York, N.Y. 10017, (212) 949-2333.