NEW YORK (TheStreet) -- Wall Street's airline analysts have made clear their opposition to disproportionate capacity growth but some airlines are growing rapidly nonetheless.

Last Friday was particularly symbolic because growth plans at three separate airlines were highlighted.On that day, Virgin America (VA) had its initial public offering, and CEO David Cush told various news outlets, including TheStreet, that the carrier will grow but not too quickly.

Virgin, with 53 A320 family aircraft in its fleet, has five airplanes coming in 2015 and five in 2016. "Long-term, we think 10% to 15% per year is a responsible rate of growth, an amount we can grow profitably," Cush said.

Investors seem pleased with the plan. In mid-morning trading Tuesday, Virgin America shares were up $2.59 to $35.27. The initial offering price was $23 a share.

Meanwhile, Spirit (SAVE - Get Report) announced Friday that it will add 10 new routes at Houston's George Bush Intercontinental Airport, where it currently has 10 destinations, all domestic. The new routes include three U.S. cities -- Baltimore, Oakland, Calif., and Tampa; three cities in Mexico and four cities in Central America. New service will begin in spring 2015.

 "The Spirit team arrived at George Bush Intercontinental Airport in 2012 offering two nonstop destinations but with this new announcement that destination total will soon stand at 22," said Mario Diaz, Houston aviation director, in a prepared statement.

In general, Wall Street has applauded Spirit's growth, which has been accompanied by growth in revenue per available seat mile.

Some analysts have looked disdainfully at Delta's (DAL - Get Report) planned growth in Seattle.

But Delta CEO Richard Anderson, in his weekly telephone message to employees, recorded late Thursday, said the airline's plan is to operate 30 gates at Seattle Tacoma International Airport.

Aviation consultant Bob Mann said no one should be surprised by growth rates at Spirit, which grew 22% in 2013 and 17.5% in the first nine months of 2014, given that its aircraft order book is well-known. Similarly, Virgin America's growth rate is known.

"There's no news in the arrival at Spirit of 50 to 100 aircraft in the next four years," he said. "The only question is where they are going to put them. And the Virgin theme is just saying what they already said, new airplanes are coming."

Mann said Delta's plan to grow to 30 gates in Seattle "seems bigger than the Seattle market would warrant, but maybe the network is pumping out so much traffic that it makes sense."

-- Written by Ted Reed in Charlotte, N.C.

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At the time of publication, the author held no positions in any of the stocks mentioned. This article is commentary by an independent contributor, separate from TheStreet's regular news coverage