The Port Authority found that any rail link to LaGuardia would face "serious funding and constructability challenges," and would take 12-13 years to complete ? with an estimated cost of $5 billion to upwards of $7 billion.

The lack of a subway connection to LaGuardia Airport (LGA) is the result of decades of political opposition, high construction costs, and geographical constraints. Since the 1940s, various plans to extend the BMT Astoria Line (N/W trains) have been proposed, but they have consistently faced fierce "Not In My Backyard" (NIMBY) pushback from residents in Astoria, Queens, who opposed the noise and disruption of an elevated track through their neighborhoods. Additionally, by the time LGA became a major hub, the surrounding areas were already densely developed, making underground tunneling prohibitively expensive—estimates for a rail link reached over $3 billion in the 1990s. More recently, a proposed "AirTrain LGA" was canceled in 2021 due to environmental concerns and criticism that its route was indirect. Consequently, LGA remains the only major New York City airport without a rail link, leaving travelers to rely on the M60/Q70 Select Bus Service, taxis, or ride-shares, which contribute to the heavy traffic congestion often seen on the Grand Central Parkway.