Estimating the current consumption of a DC motor
For general purpose motors, the rated current, input power and mechanical power are the levels at which the motor cam be operated continuously without reducing the life of the motor below the expected life. For motors sold as part of a product, the ratings are the expected maximum current for normal use. For products that are not normally used continuously for long periods of time, the current or power marked on the product may be higher than would be advisable for continuous use.

For a pump, the product input power rating would be based on the design head and flow that should be part of the pump specifications. If the pump will be operated at a different operating point you would need to calculate the input power based of the actual head, flow and efficiency. Normally the pump and motor efficiency are highest at the design head and flow.

You could estimate based on estimating what percent of head and flow you expect as a percentage of the capacity of the pump.

The situation for the air pump is probably somewhat similar, but you would need to determine what type of machine it is to know the effect of operating conditions.