You will not find anything at all like the Amex 2-4-1 voucher anywhere else. It's quite unique. [edit: in terms of opening up additional reward availability, making redemptions possible where they would otherwise not be]

In terms of short-haul out of MAN, you're looking at Ryanair, Easyjet, Jet2, maybe Tui, and some other countries airlines (Pegasus to Turkey for eg) for specific destinations.

What your best card is depends on your spending size and goals.

For the very largest spending, if it's non-cash-like MCCs, the Lloyds Bank World Elite mastercard pays 1% back in cash and is unbeatable once you're determined away from BA. Note that "cash-like MCCs" - for example gift cards, school lunch account top-ups, loan repayments - are all "cash transactions" on the Lloyds card and attract a 5% fee.

The Barclays Avios Plus card is effectively .75% back (1.5 Avios/£ spent, Avios converted to Nectar for Argos/Sainsburys) if you can use Avios as Nectar, and gives a not-as-useful cabin upgrade voucher every year (2 if you subscribe to the bank account as well for a very small net cost). If you obtain outsize value (multiple pence per Avios) on redemptions, there is **no substitute** for this cheap, accepted-everywhere, high-earning card - no matter how annoyed you are with the MAN-LHR farce and MAN T3 clown show. Remember the Avios can also be used on Aer Lingus (some options out of MAN) and Qatar.

For smaller spending amounts, there are other cashback cards in the market, you want to head over to Moneysavingexpert and read the cards section.

If you want an airline-specific card, there aren't really any to match the Amex, because of the voucher and the transferability of points to multiple airline/hotel schemes. The HSBC Premier card, which has just been revamped with a higher fee and higher earnings rate, also gives points portable to multiple schemes, and there are sometimes conversion bonuses for specific schemes - but again, nothing like the Amex voucher is available.