readarray -t array echo "${array[@]/*[aA]*/}" | xargs

1. elements in the array that containing 'a' or 'A', will be replaced by ' '(space).
2. xargs command trims leading and trailing spaces

another approach: readarray -t array printf '%s\n' "${array[@]}" | grep -Ev "a|A"

here printf prints each array element in a new line, The grep command here filters out 'a' or 'A'