Just bought a new plane and 2speed upgrades. Checked Max speed with and without bombs before and after both speed upgrades and could not detect any increase in level flight speed. I don't mind spending the coin but surely for what it cost me I should get a decent return. Anyone else noticed this when buying upgrades.

ur speed without bomb won't change a whole lot... but there is a difference... mostly the difference will be felt with the bomb attached (he higher planes with more upgrades provide much better difference)

That is what I hoped for , but did not notice a difference. Top speed on fully upgraded plane was no faster than with my other much lower spec. plane.

Which plane ?
What are your readings of speed ?
The better condition to ensure level flight is flying just above the water.