Final answer:
A reasonable tip for an airport skycap is typically $2 per bag, while $5 or $10 per bag might be considered generous. A flat rate of $2 total could be seen as inadequate for multiple bags.
Step-by-step explanation:
A reasonable tip for an airport skycap is generally $2 per bag. This amount is customary and widely accepted. Tips are a way of expressing gratitude for the skycap's service and assistance with luggage. $5 per bag or $10 per bag might be considered generous or even excessive unless the service was exceptional or the bags are exceptionally heavy or cumbersome. A flat rate of $2 total might be insufficient if you have multiple bags, as it does not adequately compensate the skycap for the additional effort required.