It's called the Southwest Effect - Southwest Airlines enters a new market (in this case Philadelphia) and the incumbent carriers watch their revenues erode. And, while it's not for everyone, the New York City and Newark airports are less than 100 miles away which means some will drive to Philadelphia for the lower fare. Granted, it's not for the business traveler but, when you have a family of 4, the savings could be substantial.
From the Travel Commerce Report
Low fares on Southwest Airlines will spur travel to and from Philadelphia, according to a new online survey conducted by the Greater Philadelphia Tourism Marketing Corporation (GPTMC). If all survey respondents who said they would visit Philly on Southwest make their intended trip, they would add a predicted $8.4 million in new direct spending to the local economy. The questionnaire yielded 10,530 responses from people living in Philadelphia and elsewhere in the United States. GPTMC conducted the survey in order to find out if the introduction of Southwest Airlines would induce more visits to Philadelphia and would motivate Philadelphia residents to travel elsewhere.
Of all the respondents, 6,251 live outside of the area, and 67 percent said they are more likely to travel to Philadelphia. On average, the respondents said they would make an additional 1.9 trips (that's a total of 11,877 trips) to Philadelphia as a result of the new low airfares available. (According to D.K. Shifflet, a leading national travel and tourism research firm, the average travel party to Philadelphia in 2001 spent $709 per trip. The $8.4 million figure comes from multiplying 11,877 trips by $709. This figure does not include spending other than purchases, lodging and dining, nor has this figure been extrapolated to the entire flying population).
Of the 4,279 respondents who live in the five-county region, 69 percent said their friends and family are more likely to visit Philadelphia because of Southwest. As for outbound travel, 92 percent of these respondents are more likely to take a trip to another city.