Tell you what, why not just fill in the Western Gap and join the Airpot to the mainland? As sailorsix pointed out you still can't get across the airport to the park. A quick glance at the map would tell you a bridge—any bridge, no matter how limited—from cityside to Hanlon's where the park starts would be a hugely expensive build and a real hazard in the harbour. So you have to look at the only other practical possibility, the Eastern Gap which as I'm sure you know was created by a storm two centuries ago, when the 'island' really was joined to the mainland. All you have to do is convince Redpath and the various cement, aggregate and shipping companies that they don't need to run ships in and outta the harbour (talk to the yachties and the Federal Port Authority too) and you'd have your bridge.
But I think it'd be easier to convince the feds to abandon their silly [air]port authority and turn the whole thing over to the City. Meantime, get your pontoon boat running from Cherry Beach ferrying cyclists and joggers over to Wards. Or get the Docks in on it and run it from Poulson. And the Authority has a swell ferry terminal nearby they'd likely be happy to rent, now that The Border's not shooting.