I've looked into this some - but if someone is better versed in the history of this stuff, please jump in.
For LGA, there have been attempts for years to extend the N train north from its current terminus in Astoria, to LGA. This is the most economical way to connect the airport to the mass transit system (there is currently no train whatsoever, the only way to LGA via public transit involves a bus).
Most proposals for this line extension called for the N train to become elevated on its approach to the airport, and the neighborhood has loudly opposed any of the nuisances that come with living next to an elevated train. This political pressure has been impossible to overcome, while tunneling has not been considered feasible or affordable.
On top of this, the state government which runs the NYC subway is reluctant to endorse this plan also, since connecting LGA to the NYC subway doesn't serve the (very important) suburban electorate. The state government has consistently pushed instead for the airport to be connected to a nearby suburban commuter rail station instead (Mets-Willets Pt on the LIRR). The political calculations behind this are pretty obvious, despite this option being far less connected to the greater transit network and promising far less ridership, and also perpetuates the need for a "monorail" transfer, like JFK and EWR.
The history of the transit situation for JFK and EWR are also interesting (and like most things NYC-infrastructure related, extensively documented), but this post is running pretty long. Happy to go into it if people are interested, but the tl;dr is: funding instability, financial downturns, squabbling fiefdoms, jurisdictional battles between NJ/NY, and the ever-present NIMBYism.
I've looked into this some - but if someone is better versed in the history of this stuff, please jump in.
For LGA, there have been attempts for years to extend the N train north from its current terminus in Astoria, to LGA. This is the most economical way to connect the airport to the mass transit system (there is currently no train whatsoever, the only way to LGA via public transit involves a bus).
Most proposals for this line extension called for the N train to become elevated on its approach to the airport, and the neighborhood has loudly opposed any of the nuisances that come with living next to an elevated train. This political pressure has been impossible to overcome, while tunneling has not been considered feasible or affordable.
On top of this, the state government which runs the NYC subway is reluctant to endorse this plan also, since connecting LGA to the NYC subway doesn't serve the (very important) suburban electorate. The state government has consistently pushed instead for the airport to be connected to a nearby suburban commuter rail station instead (Mets-Willets Pt on the LIRR). The political calculations behind this are pretty obvious, despite this option being far less connected to the greater transit network and promising far less ridership, and also perpetuates the need for a "monorail" transfer, like JFK and EWR.
The history of the transit situation for JFK and EWR are also interesting (and like most things NYC-infrastructure related, extensively documented), but this post is running pretty long. Happy to go into it if people are interested, but the tl;dr is: funding instability, financial downturns, squabbling fiefdoms, jurisdictional battles between NJ/NY, and the ever-present NIMBYism.