@Marcel Busse I have Stalker to Delta CCU (5$ + pp fee + vat), you can upgrade your alpha to a stalker then a delta, but as others pointed you will get it during IAE, just need to wait for friday, since its CNOU day. You will then be able to upgrade your alpha to a delta.
@Cugino83 unless you suggested him to buy a Mustang Beta IAE 10 years and upgrade it to a Delta after that, upgrading a ship does not upgrade insurance since CCU does not have insurance, unless the CCU is sold with a special insurance (generally special warbond CCU) which is higher than the base token.