TAMPA — At Tampa International Airport, looking to the future is a bit like a mother planning for a child's growth spurt while trying to keep him in the same size sneakers. The airport's footprint isn't getting any bigger. But my, how the passenger numbers are growing. Airport officials Tuesday unveiled the $543 million second phase of its massive expansion project that includes express curbside drop-off for passengers without checked bags and the commercial development of 17 acres of airport property. It's all part of roughly a $2.3 billion, long-term renovation and expansion that will transform the passenger experience over the next decade and allow the airport to eventually double its passenger traffic to 34 million. Related coverage: Tampa airport expansion trapped in Tallahassee crossfire The trick for the airport is to expand its property to accommodate that growth without bursting at the seams, or out of those sneakers — all while keeping the airport open for the thousands of passengers who flow through its gates every day. The centerpiece of the next phase of expansion is the "Gateway" commercial development, which includes plans for up to two hotels, an eight-story, 240,000-square-foot office building, a 20,000-square-foot retail strip and a gas station with a convenience store. Some of that office space will be leased back to the authority and its employees. Tenants for the retail strip are not yet set, though officials have previously talked about the possibility of a pet hotel or restaurants. Also not yet clear is what hotel chains might be interested in coming to the airport. The Gateway also includes a large atrium, pedestrian connections to area trails and commercial curb sides for transit and ground transportation. Phase II also includes widening the George Bean Parkway — the main artery in and out of the airport — plus adding a new exit lane and a new airport energy plant, among other items. Site preparation for the development is scheduled to start in mid-2018 with construction launching in 2019, pending board approvals. The project will stretch out until 2023. Anyone can get a peek at the project on April 27 at 6 p.m. during a public meeting at the airport's boardroom, which is on the third floor of the main terminal near the restrooms adjacent to Gateside A. Airport CEO Joe Lopano told the board of the Hillsborough County Aviation Authority at a workshop meeting that the nearly $1 billion first phase of the expansion continues the airport's efforts at innovation and passenger convenience. With perhaps a nod to legislative rumblings in Tallahassee about airport spending, Lopano said of that first phase of work: "We did what we said would do. We've done the right thing for the customer. And that's important because its our legacy. It's something we have to protect." This marks the first major renovation to the airport since the terminal was built in 1971. The first phase of the project includes a new 2.6 million-square-foot rental car facility and a new people mover train, which will connect passengers from the rental car area and economy parking garage to the main terminal. That part of the expansion is expected to be completed next year. The airport hopes to issue bonds in late 2018 to finance the project. Airport officials said favorable interest rates on a refinance of existing bonds plus the authority's efforts to fatten its financial bottom line in recent years in anticipation of this project makes the outlay well within the airport's ability to fund the construction. The per-passenger cost charged to the airlines, which provides a chunk of Tampa International's budget, will increase from the current $5.37, climbing steadily until reaching $8.24 in 2025, the airport says. But that's still far below major airports and even those of comparable size. For example, New York's JFK charges $24.62 while Portland and San Diego's airports, which are in TIA's weight class, have per-passenger fees in the $10 range. The Phase II proposal is actually a rethinking of earlier plans after the airport identified some cost savings. Those include not expanding the terminal to consolidate security checkpoint screening. That's a significant savings because it allows the airport to keep in place the current air traffic control tower and in-airport Marriott hotel. Phase I of the project was budgeted at $971 million and, among other improvements, includes new restaurants and retailers, including such local favorites as Goody Goody, Kahwa Coffee and the Cafe at Mise en Place. By next year, the new people mover and rental car facility will be open, freeing up new parking space in the airport's long-term parking garage and offering a wider choice of rental companies for travelers. A $798 million Phase III is tentatively scheduled to begin in 2023 and includes a new airside D with 16 gates capable of handling both domestic and international flights. That phase would finish in 2026. Airports have to keep ahead of their growth curve and keep the airport experience convenient, officials said. Staying static, they said, is not an option. "We have to recognize that we have to look at these sorts of things," said board chairman Robert Watkins. "We can't just sit still. We have to be thinking about what's going to be happening 15, 20, 30, 40 years from now. Others are going to have to deal with what we do or don't do today. So we need to be good stewards of what we've inherited and keep this ball moving forward so this airport can be the pride of the community that it's been." Contact William R. Levesque at [email protected] Follow @Times_Levesque.