Google maps indicates that there is room to extend the runway by about 200m at each end which would make it much more useable by these aircraft types. Expensive, yes - but not as expensive as having to overhaul jet engines more frequently (turbine blades cost big money) and having KC-30A tanker aircraft on station.
IMO it would seem to be an ideal place to spend money if we were going to spend more money to upgrade capabilities. If it was to get 2440+m it would be the second longest runway in PNG (?).
There are other upgrades happening across PNG. Hoskins for example is being extended this year to 2020m length and full asphalt. Its on New Britain, so not that far away from Manus geographically. Hoskins is better suited for much larger upgrades in length.
Randomly spending money on airport upgrades in PNG can be a bit problematic, as different provinces and islands get very competitive with each other. Operating 737 is very desirable and are seen as gateways for development of hotels and rich tourists direct from places like Australia or Fiji.
See the history of Lae and Nadzab airport (they burnt Lae airport terminal down). Nadzab was extended to operate Mirage fighters, but was never used. Its already 2440m long. And could be longer and a second large runway upgraded. 737 operations only started out of Lae in 2022.
It seems like money has been spent to make several airports in PNG (Lae, Momote, Hoskins) much better accommodate b737 or A320. Many of these have been funded by the asian development bank or via Japan directly.
Crazy crystal/spitballing idea.
Australia-PNG-Japan-US alliance would mean some more cohesive planning and possible a lot more money on these type of projects for their military dimension.
We might even forward deploy a Mogami frigate up this way, and potentially, Japan might be interested in deploying one as well. Being smaller crewed, you could fly in and fly out crews... UAV and UUV.. capabilities via hercs. Plus P8 flights start to make a lot more sense if that is the idea.
It may make sense to disperse operations across the 3 airports up in that region. You could have US marines, Japanese F-35B operating ops as part of a distributed posture. 3 airports worth of infrastructure, fuel reserves, man power, flight capabilities, 3 regions worth of hospitals, hotels, etc. It may make sense that much of the air force stuff happens out of the other two airports, and the naval stuff happens out of Manus/momote.
Historically when we have uninvited guests turn up to our region, they have spent time around this region. Namely the Russian fleet and the Chinese fleet. If the idea is to drain and wear out our capability, then having a regional naval base that can operate up to frigates, and supported by 3 airfields that can support a range of ops perpetually, then that makes that a very big ask for someone out of the region. We would always be ready for something and could bring up bigger resources when required. Being able to rearm ships at Manus would be a very nice capability to have. Being able to protect Manus and its shallow tropical waters would also be ideal. Regional engagement then also is very high, as our pacific brothers stop feeling all alone, and regular port visits would likely be in order. Being able to bring the Japanese and Americans along would be most welcome, as then its less about the random australian political wind of the day.
This is why the PNG deal imo is so critical for naval and sea power in any future conflict. All our pacific friends will be watching this very closely. Its important this works well for everyone. Now that there is this ratified alliance, more significant and long term planning can happen.