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ICBMs no. They are in space until they re-enter at about 6km.s-1. The re-entry vehicle is about the size of domestic dust bin; if you can see it, start praying fast, you have less than a second before detonation and it is close enough to kill you.
High level bombers fly at airliner altitudes (~10km), you probably won't see the actual aircraft with the naked eye but you can see the contrails.
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Maybe.
Human eye angular resolution is about 1 arc minute = 0.02 deg. That's about 0.3 m at 1 km or 3.6 m at the 12 km cruising altitude of a B2 Spirit. Its length is 21 m and wingspan is 52 m but I would suggest we use 20 m as an estimate. So we should be able to see it, in ideal conditions for a perfect eye.
As for an ICBM? Almost certainly not unless you're in the right place to see it's exhaust on its way up.
Would long range bombers or ICBMs flying overhead be visible from ground level?