Is an aircraft's maximum landing weight really weight, or is it mass? I'm calculating the lift of a Cessna 172 and I don't understand the numbers given for weight. The maximum landing weight is 2550 pounds which is nearly 1134kg. But does that mean 1134 Newtons (weight) or 1134 kilograms (mass)?

Since weight = mass x gravity, I think the weight of the C172 is in Newtons even though it's written using a unit of mass. Am I correct?
The maximum landing weight given here is actually the mass, not weight.

In general, the various 'weights' given for aircraft are masses, not weights. i.e. they are in kilograms, not Newtons.

This is simply an extension of our everyday usage. As @mins pointed out, if someone asks your weight, you tell your mass (70 kg or whatever), not the weight itself (~686N).