use warnings;
use strict;

my @aircraft = qw(AD3 DAL13 DAL14 DBR2 DBR4 DBR3 DEHA2 FG3 FG6);
my %byGroup;

push @{$byGroup{$_->[1]}}, $_->[0] for map {[/(([A-Z]+).*)/]} @aircraft;
printf "Group %5s: %s\n", $_, "@{$byGroup{$_}}" for sort keys %byGroup;