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Medium and long baseline kinematic relative positioning with a single base station will be affected by atmospheric residual errors and the ambiguities could not be fixed fast. Therefore, the performance of long-baseline relative positioning with low ambiguity-fixed rate is not as good as short-baseline situations. While considering baselines varying from short to long in airborne scenes, we propose a new method to improve the performance of kinematic relative positioning. First, high precision ionospheric delays can be easily obtained from the ambiguity-fixed resolutions in short-baseline scenes when the air just taking off. Second, the subsequent ionospheric delays are predicated epoch by epoch based on previous ionospheric delays. At last, filter with ionosphere predication constrained is implemented to fix the ambiguities quickly and obtain continuous high-precision positioning results. In this paper, the characteristics of double-differenced ionospheric residual errors for the dynamic measurement scenarios with long-baseline are analyzed. A sliding window will be applied for modeling and prediction of ionospheric delays. Next, we have discussed the implementation conditions, performance of positioning and the ambiguity resolution with this proposed method. The presented algorithm is evaluated by a set of airborne data and the results show that the new scheme can obtain the 100% fixing rate nearly and centimeter-level positioning accuracy in long baseline relative positioning with single base station as long as a few minutes short-baseline data. With this method, the costs of airborne measurement tasks will be significantly reduced.