But given the tanking dollar, these quick trips can be pricey. Taking a taxi from central Paris to Charles de Gaulle airport (or CDG) costs $50 to $80 one-way; to Orly Airport, it's $25 to $50, depending on traffic. Astoundingly, this is often more expensive than Eurostar tickets or budget airfare from Paris to a destination such as London, both of which can be as low as $50 one-way, if you book far enough ahead. Prices skyrocket at the last minute, though. Last week, I would have had to pay more than $500 for a round-trip Eurostar ticket to London. Instead, I flew for about half that on British Midland from De Gaulle to Heathrow, then experimented with ways of getting to and from the airports. These vary widely in terms of cost and convenience.
Orly Airport is closer to central Paris than CDG; I once got there by taxi at 5 a.m. in 20 minutes, for $25. But most of the budget flights I take, except Easyjet to Berlin, depart from CDG.
There are Orly and CDG buses, but to get them, I'd have to take the Metro (about $2). So it seems more efficient to stay underground and take the RER train from the big, underground labyrinth at Les Halles, which costs about $8 one-way. Last week, this airport transfer method entailed a 10-minute walk from my apartment to the St. Germain Métro stop, 10 more minutes on the train, a five-minute connection at busy Les Halles, 40 minutes on the RER, then a free bus to Terminal 1, where I caught my BMI flight to London, on a new Airbus 320. Drinks and sandwiches were served, and flying time to London was about 40 minutes. Total transfer cost: about $10. Total ground transit time: about 90 minutes. Convenience: moderate. Exhaustion level: high.
On the London side, I took the Tube's Piccadilly line from Heathrow to town, with a transfer at Green Park to the Jubilee line, re-emerging at Baker Street. Total cost: $7. Total time: 65 minutes. Convenience: moderate. Exhaustion level: very high.
From London back to Heathrow the next afternoon, I took a taxi to Paddington Station for $13, where I caught the airport express train for about $25 one-way. Total cost: $38. Total time: 60 minutes. Convenience: high. Exhaustion level: low.
Arriving back at CDG around 10 p.m., I sprang for a taxi, because I was tired and expected light traffic getting into Paris. Total cost: $50. Total time: 40 minutes. Convenience: terrific. Exhaustion level: minuscule.
Choosing the right transfer method depends on how much time, luggage and energy you have. Clearly, you get what you pay for. But I'm still experimenting.