In addition to the other comments, it's worth pointing out that (a) stealth aircraft deliberately use radar corner reflectors and other methods to increase thei

In addition to the other comments, it's worth pointing out that (a) stealth aircraft deliberately use radar corner reflectors and other methods to increase their radar signature, reserving "stealthing up" for missions that require it; (b) almost all forms of identifying and locating an aircraft in flight besides radar require it to be transmitting RF (eg ads!) yet the conditions likely to lead to ejection likely lead to a reduction in the ability to do this; and (c) search and rescue in deep water is really really hard as water strongly absorbs and scatters most forms of radiation likely to be used .