NO+ and NO are derivative of N2.
For NO, we have total 7 + 8 = 15 electrons
NO has 10 bonding electrons and 5 antibonding elelctrons.
We know, Bond order = 12(Bonding electron - non bonding electron)
Bond order for NO = 12(10- 5) = 2.5
For NO+, we have 7 + 8 - 1 = 14 electrons
i.e 10 bonding electrons and 4 antibonding electrons
So, Bond order = 12(10 -4) = 3
NO+ bond order = 3
NO bond order = 2.5
⇒3+2.5=5.5