Most new homes these days have a suspended beam and block ground floor. These will have an air gap under to floor as they are suspended (span between walls) above the ground.
Air bricks at 2500mm centres are required in warranty standards and should have been noted they were missing with warranty inspections. You Professional Snagging Inspector should have also noted this.
It is not just an air brick, but the air supply needs to be ducted using a "periscope vent" to under the floor.
You may have a solid, ground bearing concrete floor (no airbricks required) and your neighbours have a beam and block suspended ground floor as perhaps the backfilling would exceed 600mm for solid floor if, the air brick houses are built on a sloping ground.
You should check your NHBC warranty card as this will details what type of ground floor you have for your home, assuming it was in fact, filled out correctly. You can now ask for all records of building Inspections made to your house during construction. Ground bearing (solid) concrete floors (that is the ground they rest on and the damp proof membrane), must be inspected before the concrete is poured.