BY PLANE
Flying from New York to Lisbon typically costs less than from New York to Paris, Amsterdam, or Frankfurt. In today’s marketplace, one airline proposes a fare structure, and another airline follows with a competing and perhaps different fare structure. The competition might or might not result in uniform prices for all airlines flying to that particular country. It all adds up to chaos—but often beneficial chaos for the alert traveler willing to study and consider all the fares available. The key to bargain airfares is to shop around. Flying time from New York to Lisbon is about 6 hours; from Atlanta to Lisbon is about 6 1/2 hours.

MAJOR AIRLINES
When it was established in 1946, TAP (800/221-7370; www.tap-airportugal.pt), The national airline of Portugal, flew only between Lisbon and Angola and Mozambique (then Portuguese colonies). Today TAP flies to four continents and has one of the youngest fleets in the airline industry—its aircraft have an average age of only 4 years. Its U.S. gateway is Newark, New Jersey. In Portugal, it flies to three destinations, the most popular of which are Lisbon, Porto and Faro.

Continental Airlines (800/525-0280 in the U.S.; www.continental.com) began flying to Lisbon from Newark International Airport in 1997. The increased capacity comes as a welcome addition to existing air service, particularly during heavy travel periods in summer.

Air Canada (800/247-2262 in the U.S. or Canada; www.aircanada.ca) no longer offers direct flights to Lisbon, but it does offer daily flights from Toronto and Montreal to Paris, where you can transfer to another carrier to reach Lisbon.

For flights from the U.K., contact British Airways (0845/773-3377,or 0345/222-111 outside Londonwww.british-airways.com) or TAP, Gillingham House, 3844 Gillingham St., London SW1V 1JW (0845/601-0932).

TAP also has frequent flights on popular routes from major cities in western Europe. Its flights to Lisbon from London are an especially good deal; sometimes they’re priced so attractively that one might combine a sojourn in England with an inexpensive side excursion to Portugal. TAP gives passengers the option of stopping midway across the Atlantic in the Azores, and it makes baggage transfers and seat reservations on connecting flights within Portugal much easier.

REGULAR FARES
All airlines divide their calendar year into three seasons—basic, shoulder, and peak— whose dates might vary slightly from airline to airline. TAP’s basic season is November 1 to December 14 and December 25 to March 31. The most expensive season is its peak season from June 1 to September 15, when passengers tend to solidly book most transatlantic flights. Other dates are shoulder season.

DISCOUNTED FARES
All the major carriers offer an APEX ticket, generally the cheapest transatlantic option. Usually such a ticket must be purchased 14 to 21 days in advance, and a stay in Europe must last at least 7 days but not more than 30. Changing the date of departure from North America within 21 days of departure sometimes entails a penalty of around $150; with some tickets, no changes of any kind are permitted. A more flexible (but more expensive) option is the regular economy fare. This ticket offers the same seating and services as the APEX ticket for a shorter stay than the 7-day APEX minimum requirement. One of the most attractive side benefits of an economy-class ticket is the absolute freedom to make last-minute changes in flight dates and unrestricted stopovers.

For families, one strong attraction of TAP is that infants under 2 years pay 10% of the adult fare. (About a half dozen bassinets are available on transatlantic flights, allowing parents to lift infants off their laps onto specially designed brackets during certain segments of the flight.) Children under 12 pay 75% of the adult price for most categories of tickets. TAP offers a winter senior citizen fare from its three U.S. gateways to anywhere in Portugal. The discount is 10% off published fares. The discount applies for seniors (travelers 62 years of age or older) plus a companion of any age (spouse, grandchild, or friend). The maximum stay abroad with this type of ticket is 2 months. Tickets must be purchased at least 14 days before departure.

Subject to change, TAP offers a oneway youth fare. It’s 50% off the regular fare, depending on the season, between New York or Boston and Lisbon. Tickets of this type can be purchased only at the last minute because they can be booked only within 72 hours of departure. Youth fares are offered only to travelers aged 12 to 24 and only if space is available. They cannot be mailed and must be purchased in person at a travel agent or any TAP counter.

None of the above options takes into account promotional fares airlines might initiate while you’re planning your trip. These are usually particularly attractive during the basic season. Clients who prefer not to specify when they’ll return home, or who can’t purchase their tickets within 21 days before takeoff, usually opt for TAP’s excursion fare. It costs more than either APEX option but has no restrictions on advance purchases or time of travel. The airline’s most exclusive and most expensive class of service is named after the seafaring pioneers who spread Portugal’s empire throughout the world. Navigator Class passengers benefit from better service and upgraded food and drink. This is TAP’s version of business class, comparable to first class on other major carriers.