I think we are coming from same place on this.
I buying Alaskan pollock fish frozen in Lidl that was caught in 2017 and this was before crisis started.
I know we diverging from the air travel bit but chickens from hatch to plate is 30 days minimum but reality closer to 40 so anything hatched on 1st March is ready.
Beef is a lot longer but there is massive amount there plus add in sheep / pork then there will not be a lack of protein.
Wheat crops worldwide will be high, Russia is massive producer with huge exports that outstripping US.
Fruit and Veg will be an issue due to the floods last winter in Lincolnshire / Norfolk / Suffolk, add in the issues across Europe and there will be issues come summer because countrys will want to hold for safety stock rather than export.
There likely enough apples for a couple of years, mainly in sheds where CO2 is reduced to prolong life plus reduce cider crop in Herefordshire to human consumption.
Issue is picking and logistics.