CART, the Council Aviation Recovery Task Force, outlined the stages of resumption of passenger air travel. At the time it published its guidance, it said most of commercial passenger aviation was in Stage 0 or Stage 1.
STAGE 0:
Travel restrictions and only minimal movement of passengers between major airports.
STAGE 1:
Initial increase of passenger travel. This will coincide with relatively low passenger volumes, allowing airlines and airports to introduce public health practices appropriate to the volume. Health measures for travel required at airports will need to, at a minimum, match those from other local modes of transport and infrastructure.
STAGE 2:
As health authorities review the applicability of measures based on recognised medical criteria, passenger volumes will continue to increase. Several measures that were required in Stages 0 and 1 may be lifted.
STAGE 3:
May occur when the outbreak has been sufficiently contained in a critical mass of major destinations worldwide as determined by health authorities. Reduction of national health alert levels and associated loosening of travel restrictions will be key triggers. Risk mitigation measures will continue to be reduced, modified, or will be stopped. Effective pharmaceutical interventions (e.g. therapies or vaccines) may not be commonly available during Stage 3, but contact tracing and testing should be readily available.
STAGE 4:
Begins when specific and effective pharmaceutical interventions readily available in most countries. There may be a set of residual measures/mitigations that could be retained, although these too should undergo periodic review.
