They launch from a static airfield and require super special ground crews/supply lines though. We can safely launch them from a US airfield but I'm not sure what safety means in an era of cheap drones and hypersonic weapons. Maybe it's a viable first strike, maybe it's only a first strike before airfields are unusable. Subs are totally hidden for 6-12 months at a time unless you detect them temporarily. A CVN's top speed is classified but carrier groups can probably move at a destroyer's pace. Those have a lot of flexibility so it's like the old ICBM/submarine nuke debate.