Federal officials are urging Southern Nevadans to speak up about a proposed international airport near Las Vegas, but few local citizens weighed in at a series of forums this week.

Officials from the Federal Aviation Authority and the Bureau of Land Management were in Jean and Las Vegas from Tuesday through Thursday gathering public comments on the potential environmental impact of an airport 30 miles south of Las Vegas.

Jeffrey Steinmetz, a planning and environmental coordinator in the Las Vegas field office of the Bureau of Land Management, said public attendance was light at the three events.

A total of 10 citizens spoke at the meetings, Steinmetz said.

The proposed airport, in the Ivanpah Valley along Interstate 15 three miles north of the California state line, would supplement McCarran International Airport after McCarran reaches its flier capacity of 53 million. County aviation executives have said McCarran could hit that passenger ceiling as early as 2011.

Federal officials are studying the environmental effects of the Ivanpah airport's first phase, which could open as early as 2017 and could accommodate as many as 20 million passengers a year. A second phase that could handle up to 35 million passengers annually would require a separate environmental impact statement.

This week's presentations included an 18-minute narrated slide show explaining the looming capacity constraints at the 3,000-acre McCarran.

McCarran's four runways handled 614,000 air operations -- takeoffs or landings -- in 2005, up from 400,000 air operations in 1990, the presentation noted. Passenger traffic through McCarran rose from 18.6 million in 1990 to 42.4 million in 2005, making McCarran the nation's fifth-busiest airport last year.

McCarran's flight operations will surpass the 700,000 mark sometime around 2018, at which point the airport will reach an "unacceptable level of airfield delay," the slide show's narrator said. And if annual air operations at McCarran were to reach a projected 922,000 by about 2025, the show said, gridlock would reign inside terminals, at baggage-claim areas, on surrounding roadways and on the tarmac. Delays of up to several hours could affect some flights during peak travel hours.

The slide show pointed to numerous improvements planned or under way at McCarran, including a third terminal, additional parking garages and a consolidated car-rental center, but it concluded that McCarran would not be able to handle the sheer volume of air traffic into Southern Nevada beyond 2018.

The presentation, said officials of the Clark County Department of Aviation and the Federal Aviation Authority, considered several solutions to the coming traffic crunch at McCarran, including expanding McCarran, adding to other airports in the county or building a new commercial passenger and cargo airport in the Ivanpah Valley.

After accounting for each option's land availability, consistency with surrounding uses, roadway access and airspace compatibility, county officials settled on the Ivanpah alternative, which would consist of a 5,934-acre airport. An additional 16,903 acres of surrounding land would act as a noise-compatibility buffer to prevent inappropriate residential development nearby, similar to McCarran's 5,300-acre Cooperative Management Area west of the airport in southwest Las Vegas.

The Ivanpah airport would serve longer domestic flights, international flights, cargo planes and charter travel.

Getting an airport off the ground in Ivanpah, however, will require an environmental impact statement assessing the project's effects on air quality, wildlife, historic and archaeological sites, wetlands, water quality and surface transportation, among other areas. The environmental study would also weigh the airport's light emissions, noise volume and visual impacts.

Steinmetz said forum attendees have expressed worries about the protection of desert tortoise habitats in the Ivanpah Valley, the proposed airport's effects on water resources and the prospect of urban sprawl fanning out beyond the airport.

The biggest contingent of concerned neighbors, however, has been the off-road vehicle enthusiasts who use the Ivanpah Valley for races and other events, Steinmetz said.

Locals Ken Freeman, a contractor, and John Pellissier, an HVAC engineer, are both members of Southern Nevada Offroad Enthusiasts, a 37-year-old club that Pellissier said has been racing in the Ivanpah Valley for more than 20 years. Both men were at Thursday's meeting inside St. John the Baptist Greek Orthodox Church at 5300 S. El Camino Road in Las Vegas.

Pellissier said since the Bureau of Land Management sold the Ivanpah airport land to Clark County in 2004, his club has had a tough time accessing the site for activities. Tracks are shorter now that the proposed airport's acreage is closed for environmental studies, and the group has paid charges of $1,000 to $5,500 for permit fees and for incursions into "critical areas," Pellissier said.

He added that the Ivanpah Valley also harbors events for the Boy Scouts of America, and serves as a staging area for windsurfers, sky-jumpers and other outdoor lovers.

"There's no place else for these people to recreate," Pellissier said. "Where are we to go next?"

Freeman said he was also concerned about the environmental implications of an airport in Ivanpah.

There's no infrastructure in the area, and the county would have to pipe water into the development, Freeman said. That could mean less water for residential users in the Las Vegas Valley, he said. Also, commuting passengers and cargo trucks could further clog an already congested I-15, he said.

Freeman said he'd rather see the Clark County Department of Aviation expand the Henderson Executive Airport into a supplemental commercial airfield. It's closer to town, and tourists would face a shorter trek from the terminal to the Strip, he said.

Rosemary Vassiliadis, deputy director of the Clark County Department of Aviation, said in an interview following the meeting that the Henderson airport was never designed for commercial air travel. The runways are too short to handle large jets, she said, and existing residential neighborhoods around the airfield prohibit its expansion.

Andy Richards, manager of the Federal Aviation Authority's district office in San Francisco, said his agency will analyze every public comment and offer responses in its official environmental impact statement.

He added that the authority will accept public comments throughout the study process.

Officials said it could take more than three years to assemble an impact statement.

They said a draft statement should be complete in late 2008, with a final report ready in fall 2009.

Richards said federal officials could schedule more public meetings in Southern Nevada in the next nine months to a year.

In the meantime, citizens can e-mail comments to snvairporteis@vhb.com. They can also sign up for a regular newsletter at the project's Web site, at www.snvairporteis.com.